{"messages":[{"content":"You are a constitutional council ranking individual git commits for ownership allocation.\n\nCompare these two commits. Decide which contributed more lasting value to the project.\n\nJudge substance, not spectacle:\n- Prefer correct, lasting design and real bugfixes over churn, formatting, renames, or generated noise.\n- Prefer clarity and necessity over sheer line count. A small precise change can beat a large diffuse one.\n- Do not favor a side merely because its patch is longer or noisier.\n- Weight what the change does for the project, not the contributor's name.\n\nReturn ONLY a JSON object: {\"winner\": \"A\" or \"B\", \"ratio\": \"N:M\", \"explanation\": \"...\"}\nThe explanation must cite concrete differences in the patches (1-3 sentences).\n\nSide A — contributor: tommy-mor\nSide A — commit message:\n[af73743d] Replace GroupState with ScopeVotes and derive edges at ranking time.\n\nStore only uuid_votes and recent_votes per scope; rank centrality and pair logic rebuild edge weights on demand instead of maintaining cached state.\n\nCo-authored-by: Cursor <cursoragent@cursor.com>\n\nSide A — unified diff (full patch):\ndiff --git a/server/src/events.rs b/server/src/events.rs\nindex 8a166d49b4f26835fbc2b58cb1f4bdbf002763b8..015208311f6c5c23a0e8aab068d002a69c89c4e1 100644\n--- a/server/src/events.rs\n+++ b/server/src/events.rs\n@@ -43,7 +43,7 @@ pub enum ViewEvent {\n #[derive(Debug, Clone, Serialize, Deserialize)]\n #[serde(tag = \"type\", rename_all = \"snake_case\")]\n pub enum Event {\n-    /// Pairwise comparison vote (replayed into the parent node's [`crate::reducer::GroupState`] on boot).\n+    /// Pairwise comparison vote (replayed into the parent node's [`crate::reducer::ScopeVotes`] on boot).\n     /// `scope` is the parent [`crate::path_types::ItemId`] string; empty string is the tree root.\n     VoteRecorded {\n         ts: i64,\ndiff --git a/server/src/html/mod.rs b/server/src/html/mod.rs\nindex 4eff2e19ed4d303ff8e80c1eabd8a15b4990e643..1e2e7a06856d8a62378741aaf5ed94a4ffed337e 100644\n--- a/server/src/html/mod.rs\n+++ b/server/src/html/mod.rs\n@@ -13,7 +13,7 @@ use crate::{\n     form_template::template_json_compact,\n     path_types::ItemId,\n     ranking::{\n-        connected_components_from_voted_pairs, ranked_items_subset, RankedItem, MAX_ITERS, TOL,\n+        ranked_items_subset, scope_components, RankedItem, MAX_ITERS, TOL,\n     },\n     reducer::{GlobalTree, NodeState},\n     state::AppState,\n@@ -397,10 +397,9 @@ pub fn ranking_panel_with_highlights(\n     tree: &GlobalTree,\n     highlighted: &HashSet<ItemId>,\n ) -> Markup {\n-    let group = &node.local_ranking;\n-    let n = group.idx_to_item.len();\n-    let (comps, _isolates) =\n-        connected_components_from_voted_pairs(n, group.voted_pairs.iter().copied());\n+    let scope = &node.votes;\n+    let (comps, _isolates, _) =\n+        scope_components(scope);\n \n     // Each connected component of voted items is its own ranking; isolated and\n     // never-voted children fall into the \"unranked\" bucket below.\n@@ -410,7 +409,7 @@ pub fn ranking_panel_with_highlights(\n         if comp.len() < 2 {\n             continue;\n         }\n-        let ranked = ranked_items_subset(group, comp, MAX_ITERS, TOL);\n+        let ranked = ranked_items_subset(scope, comp, MAX_ITERS, TOL);\n         for r in &ranked {\n             ranked_ids.insert(r.item.clone());\n         }\ndiff --git a/server/src/html/vote.rs b/server/src/html/vote.rs\nindex bf82aef3ad9c5f4e9e877c47dab27beb29a80b8f..3aa00c417c89a9cab3417c650b50ed7c73f08e20 100644\n--- a/server/src/html/vote.rs\n+++ b/server/src/html/vote.rs\n@@ -14,7 +14,7 @@ use crate::{\n     html::{ranking_panel_with_highlights, scope_theme_style, JsBuilder},\n     pair::{children_of, resolve_pair, suggest_next_pair_in_pool},\n     path_types::ItemId,\n-    reducer::{GlobalTree, GroupState, NodeState, VoteData},\n+    reducer::{GlobalTree, NodeState, ScopeVotes, VoteData},\n     state::{parse_item_param, AppState},\n     ui_action::UI_RPC_FIELD,\n };\n@@ -68,8 +68,8 @@ fn ratios_for_page(v: &VoteData, page_left: &ItemId, page_right: &ItemId) -> (i3\n     }\n }\n \n-fn edge_votes(group: &GroupState, left: &ItemId, right: &ItemId) -> Vec<VoteData> {\n-    group\n+fn edge_votes(scope: &ScopeVotes, left: &ItemId, right: &ItemId) -> Vec<VoteData> {\n+    scope\n         .recent_votes\n         .iter()\n         .filter(|v| {\n@@ -113,11 +113,11 @@ fn slider_value_from_ratios(r_left: i32, r_right: i32) -> i32 {\n \n fn vote_edge_history(\n     tree: &GlobalTree,\n-    group: &GroupState,\n+    scope: &ScopeVotes,\n     left: &ItemId,\n     right: &ItemId,\n ) -> Markup {\n-    let mut votes = edge_votes(group, left, right);\n+    let mut votes = edge_votes(scope, left, right);\n     votes.sort_by(|a, b| b.ts.cmp(&a.ts));\n     let legend_left = child_title(tree, left);\n     let legend_right = child_title(tree, right);\n@@ -228,9 +228,9 @@ pub(crate) fn vote_recorded_morph(\n ) -> JsBuilder {\n     let pool = children_of(tree, parent);\n     let empty = NodeState::default();\n-    let group = tree.get(parent).unwrap_or(&empty).local_ranking.clone();\n-    let edge_history = vote_edge_history(tree, &group, left, right);\n-    let next_pair = suggest_next(&group, left, right, &pool);\n+    let scope = tree.get(parent).unwrap_or(&empty).votes.clone();\n+    let edge_history = vote_edge_history(tree, &scope, left, right);\n+    let next_pair = suggest_next(&scope, left, right, &pool);\n     let actions = vote_compare_actions(parent, next_pair.as_ref());\n     let sidebar = vote_ranking_sidebar(tree, parent, left, right);\n     JsBuilder::new()\n@@ -252,12 +252,12 @@ fn vote_compare_item_card(tree: &GlobalTree, item: &ItemId, side_class: &str) ->\n }\n \n fn suggest_next(\n-    group: &GroupState,\n+    scope: &ScopeVotes,\n     left: &ItemId,\n     right: &ItemId,\n     pool: &[ItemId],\n ) -> Option<(ItemId, ItemId)> {\n-    suggest_next_pair_in_pool(group, pool, Some((left, right)))\n+    suggest_next_pair_in_pool(scope, pool, Some((left, right)))\n }\n \n pub async fn vote_page(\n@@ -284,9 +284,9 @@ pub async fn vote_page(\n         };\n \n     let pool = children_of(&tree, &parent);\n-    let group = &parent_node.local_ranking;\n-    let next_pair = suggest_next(group, &left, &right, &pool);\n-    let edge_history = vote_edge_history(&tree, group, &left, &right);\n+    let scope = &parent_node.votes;\n+    let next_pair = suggest_next(&scope, &left, &right, &pool);\n+    let edge_history = vote_edge_history(&tree, &scope, &left, &right);\n \n     let rpc_json = template_json_compact(&serde_json::json!({\n         \"action\": \"record_vote\",\n@@ -388,8 +388,8 @@ mod polarity_tests {\n         let mut tree = GlobalTree::new();\n         tree.apply_vote(&parent, vote, TEST_ACTOR_UUID);\n \n-        let group = &tree.get(&parent).unwrap().local_ranking;\n-        let ranked = ranked_items(group);\n+        let scope = &tree.get(&parent).unwrap().votes;\n+        let ranked = ranked_items(scope);\n         assert_eq!(\n             ranked[0].item, left,\n             \"left item should rank first when ratio favours the left\"\ndiff --git a/server/src/pair.rs b/server/src/pair.rs\nindex 42a1b1eb2adf16730d34d0fe23c13d5a75d7ba27..9873295c51526726089875bbfd2f97d7faa91872 100644\n--- a/server/src/pair.rs\n+++ b/server/src/pair.rs\n@@ -11,8 +11,8 @@ use std::collections::{HashMap, HashSet};\n \n use crate::{\n     path_types::ItemId,\n-    ranking::{connected_components_from_voted_pairs, ranked_items},\n-    reducer::{GlobalTree, GroupState},\n+    ranking::{pair_is_voted, ranked_items, scope_components},\n+    reducer::{GlobalTree, ScopeVotes},\n };\n \n fn pairs_match(a: &ItemId, b: &ItemId, x: &ItemId, y: &ItemId) -> bool {\n@@ -23,26 +23,15 @@ fn pair_excluded(a: &ItemId, b: &ItemId, exclude: Option<(&ItemId, &ItemId)>) ->\n     exclude.is_some_and(|(x, y)| pairs_match(a, b, x, y))\n }\n \n-fn pair_is_voted(group: &GroupState, a: &ItemId, b: &ItemId) -> bool {\n-    let Some(&ai) = group.item_to_idx.get(a) else {\n-        return false;\n-    };\n-    let Some(&bi) = group.item_to_idx.get(b) else {\n-        return false;\n-    };\n-    let (i, j) = if ai < bi { (ai, bi) } else { (bi, ai) };\n-    group.voted_pairs.contains(&(i, j))\n-}\n \n struct ComponentLayout {\n     ids: HashMap<ItemId, usize>,\n     established: HashSet<usize>,\n }\n \n-fn component_layout(group: &GroupState, pool: &[ItemId]) -> ComponentLayout {\n-    let n = group.idx_to_item.len();\n-    let (comps, isolates) =\n-        connected_components_from_voted_pairs(n, group.voted_pairs.iter().copied());\n+fn component_layout(scope: &ScopeVotes, pool: &[ItemId]) -> ComponentLayout {\n+    let (comps, isolates, idx_to_item) = scope_components(scope);\n+    let n = idx_to_item.len();\n \n     let mut established = HashSet::new();\n     let mut ids: HashMap<ItemId, usize> = HashMap::new();\n@@ -52,14 +41,14 @@ fn component_layout(group: &GroupState, pool: &[ItemId]) -> ComponentLayout {\n         }\n         for &idx in comp {\n             if idx < n {\n-                ids.insert(group.idx_to_item[idx].clone(), comp_idx);\n+                ids.insert(idx_to_item[idx].clone(), comp_idx);\n             }\n         }\n     }\n     let mut next = comps.len();\n     for &idx in &isolates {\n         if idx < n {\n-            ids.insert(group.idx_to_item[idx].clone(), next);\n+            ids.insert(idx_to_item[idx].clone(), next);\n             next += 1;\n         }\n     }\n@@ -121,7 +110,7 @@ fn established_groups_in_pool<'a>(\n     groups\n }\n \n-fn ranked_pool_order(group: &GroupState, pool: &[ItemId]) -> Vec<ItemId> {\n+fn ranked_pool_order(group: &ScopeVotes, pool: &[ItemId]) -> Vec<ItemId> {\n     let pool_set: HashSet<_> = pool.iter().collect();\n     ranked_items(group)\n         .into_iter()\n@@ -132,7 +121,7 @@ fn ranked_pool_order(group: &GroupState, pool: &[ItemId]) -> Vec<ItemId> {\n \n /// Walk 1↔2, 2↔3, …; optional `require_unvoted` skips voted edges.\n fn zip_adjacent_pair(\n-    group: &GroupState,\n+    group: &ScopeVotes,\n     order: &[ItemId],\n     exclude: Option<(&ItemId, &ItemId)>,\n     require_unvoted: bool,\n@@ -153,7 +142,7 @@ fn zip_adjacent_pair(\n \n /// Grow the voted graph toward one component (no rank centrality).\n fn suggest_grow_pair(\n-    group: &GroupState,\n+    group: &ScopeVotes,\n     pool: &[ItemId],\n     layout: &ComponentLayout,\n     exclude: Option<(&ItemId, &ItemId)>,\n@@ -216,7 +205,7 @@ fn suggest_grow_pair(\n \n /// Pick the next pair to vote on within `pool`.\n pub fn suggest_next_pair_in_pool(\n-    group: &GroupState,\n+    group: &ScopeVotes,\n     pool: &[ItemId],\n     exclude: Option<(&ItemId, &ItemId)>,\n ) -> Option<(ItemId, ItemId)> {\n@@ -315,7 +304,7 @@ pub fn resolve_pair(\n         (None, None) => {\n             let group = tree\n                 .get(parent)\n-                .map(|n| &n.local_ranking)\n+                .map(|n| &n.votes)\n                 .cloned()\n                 .unwrap_or_default();\n             suggest_next_pair_in_pool(&group, &children, None).ok_or(PairError::NoPair)\n@@ -398,7 +387,7 @@ mod tests {\n                 \"https://reddit.com/r/rust/b\",\n             ],\n         );\n-        let group = tree.get(&parent).unwrap().local_ranking.clone();\n+        let group = tree.get(&parent).unwrap().votes.clone();\n         let pool = children_of(&tree, &parent);\n         assert!(!pair_is_voted(&group, &pool[0], &pool[1]));\n         assert!(suggest_next_pair_in_pool(&group, &pool, None).is_some());\n@@ -417,7 +406,7 @@ mod tests {\n         );\n         let vote = test_vote(1, \"https://reddit.com/r/rust/a\", \"https://reddit.com/r/rust/b\", 2, 1);\n         apply(&mut tree, &parent, vote);\n-        let group = tree.get(&parent).unwrap().local_ranking.clone();\n+        let group = tree.get(&parent).unwrap().votes.clone();\n         let pool = children_of(&tree, &parent);\n         let (l, r) = suggest_next_pair_in_pool(&group, &pool, None).unwrap();\n         let voted_ab = (l.as_str() == \"https://reddit.com/r/rust/a\" && r.as_str() == \"https://reddit.com/r/rust/b\")\n@@ -441,7 +430,7 @@ mod tests {\n         let cd = test_vote(2, \"https://reddit.com/r/rust/c\", \"https://reddit.com/r/rust/d\", 2, 1);\n         apply(&mut tree, &parent, ab);\n         apply(&mut tree, &parent, cd);\n-        let group = tree.get(&parent).unwrap().local_ranking.clone();\n+        let group = tree.get(&parent).unwrap().votes.clone();\n         let pool = children_of(&tree, &parent);\n         let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();\n         let chosen = pair_set(&pair);\n@@ -467,7 +456,7 @@ mod tests {\n         );\n         let ab = test_vote(1, \"https://reddit.com/r/rust/a\", \"https://reddit.com/r/rust/b\", 2, 1);\n         apply(&mut tree, &parent, ab);\n-        let group = tree.get(&parent).unwrap().local_ranking.clone();\n+        let group = tree.get(&parent).unwrap().votes.clone();\n         let pool = children_of(&tree, &parent);\n         let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();\n         let chosen = pair_set(&pair);\n@@ -496,7 +485,7 @@ mod tests {\n         );\n         let ab = test_vote(1, \"https://reddit.com/r/rust/a\", \"https://reddit.com/r/rust/b\", 2, 1);\n         apply(&mut tree, &parent, ab);\n-        let group = tree.get(&parent).unwrap().local_ranking.clone();\n+        let group = tree.get(&parent).unwrap().votes.clone();\n         let pool = children_of(&tree, &parent);\n         let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();\n         let chosen = pair_set(&pair);\n@@ -522,7 +511,7 @@ mod tests {\n             let v = test_vote(1, a, b, l, r);\n             apply(&mut tree, &parent, v);\n         }\n-        let group = tree.get(&parent).unwrap().local_ranking.clone();\n+        let group = tree.get(&parent).unwrap().votes.clone();\n         let pool = children_of(&tree, &parent);\n         let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();\n         let chosen = pair_set(&pair);\n@@ -550,7 +539,7 @@ mod tests {\n             let v = test_vote(1, a, b, l, r);\n             apply(&mut tree, &parent, v);\n         }\n-        let group = tree.get(&parent).unwrap().local_ranking.clone();\n+        let group = tree.get(&parent).unwrap().votes.clone();\n         let pool = children_of(&tree, &parent);\n         let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();\n         let chosen = pair_set(&pair);\ndiff --git a/server/src/projection_store.rs b/server/src/projection_store.rs\nindex 27fc0bb0519d9f035dceec1fc8b0fa74b00b6b40..8c1a466183a96173fe52b144fb67c2454b715fbd 100644\n--- a/server/src/projection_store.rs\n+++ b/server/src/projection_store.rs\n@@ -214,7 +214,7 @@ mod tests {\n \n         let loaded = store.load_tree().unwrap();\n         let root = loaded.get(&ItemId::root()).unwrap();\n-        assert_eq!(root.local_ranking.idx_to_item.len(), 2);\n+        assert_eq!(crate::ranking::ranked_items(&root.votes).len(), 2);\n         assert!(root.children.contains(&ItemId::opaque(\"alpha\")));\n     }\n \ndiff --git a/server/src/ranking.rs b/server/src/ranking.rs\nindex 1fc3298d2b2864e9711cd262a034677e45c7090c..cc4de6da11b02135e5e6b1d2a68646cb77870b9d 100644\n--- a/server/src/ranking.rs\n+++ b/server/src/ranking.rs\n@@ -1,7 +1,7 @@\n-use std::collections::{HashMap, HashSet};\n+use std::collections::{BTreeSet, HashMap, HashSet};\n \n use crate::path_types::ItemId;\n-use crate::reducer::GroupState;\n+use crate::reducer::{canonical_pair_ids, ScopeVotes};\n \n #[derive(Debug, Clone)]\n pub struct RankedItem {\n@@ -9,15 +9,76 @@ pub struct RankedItem {\n     pub score: f64,\n }\n \n-/// Power-iteration cap and convergence tolerance for rank centrality.\n pub const MAX_ITERS: usize = 10_000;\n pub const TOL: f64 = 1e-8;\n \n-/// Compute connected components over the voted-pairs graph (treated as undirected).\n-///\n-/// Returns:\n-/// - `components`: each component is a sorted list of node indices, excluding isolates.\n-/// - `isolates`: sorted list of node indices with degree 0 (no voted pairs).\n+pub fn item_index(scope: &ScopeVotes) -> (HashMap<ItemId, usize>, Vec<ItemId>) {\n+    let mut item_strs: BTreeSet<String> = BTreeSet::new();\n+    for vote in scope.uuid_votes.values() {\n+        item_strs.insert(vote.a.as_str().to_string());\n+        item_strs.insert(vote.b.as_str().to_string());\n+    }\n+    let mut idx_to_item: Vec<ItemId> = Vec::with_capacity(item_strs.len());\n+    let mut item_to_idx: HashMap<ItemId, usize> = HashMap::with_capacity(item_strs.len());\n+    for s in item_strs {\n+        let id = ItemId::from_storage(&s).unwrap_or_else(|| ItemId::opaque(&s));\n+        let idx = idx_to_item.len();\n+        item_to_idx.insert(id.clone(), idx);\n+        idx_to_item.push(id);\n+    }\n+    (item_to_idx, idx_to_item)\n+}\n+\n+pub fn edges_from_scope(scope: &ScopeVotes) -> HashMap<(usize, usize), f64> {\n+    let (item_to_idx, _) = item_index(scope);\n+    let mut edges: HashMap<(usize, usize), f64> = HashMap::new();\n+    for vote in scope.uuid_votes.values() {\n+        let Some(&ai) = item_to_idx.get(&vote.a) else {\n+            continue;\n+        };\n+        let Some(&bi) = item_to_idx.get(&vote.b) else {\n+            continue;\n+        };\n+        let w_a = vote.ratio_left as f64 * vote.trust_weight;\n+        let w_b = vote.ratio_right as f64 * vote.trust_weight;\n+        if w_a > 0.0 {\n+            *edges.entry((bi, ai)).or_insert(0.0) += w_a;\n+        }\n+        if w_b > 0.0 {\n+            *edges.entry((ai, bi)).or_insert(0.0) += w_b;\n+        }\n+    }\n+    edges\n+}\n+\n+pub fn edge_weight_sum(scope: &ScopeVotes) -> f64 {\n+    edges_from_scope(scope).values().sum()\n+}\n+\n+pub fn voted_pair_indices(scope: &ScopeVotes) -> HashSet<(usize, usize)> {\n+    let (item_to_idx, _) = item_index(scope);\n+    let mut pairs = HashSet::new();\n+    for vote in scope.uuid_votes.values() {\n+        let Some(&ai) = item_to_idx.get(&vote.a) else {\n+            continue;\n+        };\n+        let Some(&bi) = item_to_idx.get(&vote.b) else {\n+            continue;\n+        };\n+        let (i, j) = if ai < bi { (ai, bi) } else { (bi, ai) };\n+        pairs.insert((i, j));\n+    }\n+    pairs\n+}\n+\n+pub fn pair_is_voted(scope: &ScopeVotes, a: &ItemId, b: &ItemId) -> bool {\n+    let (lo, hi) = canonical_pair_ids(a, b);\n+    scope\n+        .uuid_votes\n+        .keys()\n+        .any(|(_, l, h)| l == &lo && h == &hi)\n+}\n+\n pub fn connected_components_from_voted_pairs(\n     n: usize,\n     voted_pairs: impl Iterator<Item = (usize, usize)>,\n@@ -63,20 +124,25 @@ pub fn connected_components_from_voted_pairs(\n     (comps, isolates)\n }\n \n-/// Compute rank-centrality scores for the whole group and return items sorted\n-/// by score (descending). Recomputed fresh from the edge set on every call —\n-/// there is no score cache.\n-pub fn ranked_items(group: &GroupState) -> Vec<RankedItem> {\n-    let n = group.idx_to_item.len();\n-    let scores =\n-        compute_scores_from_edges(n, group.edges.iter().map(|(&k, &w)| (k, w)), MAX_ITERS, TOL);\n+pub fn scope_components(scope: &ScopeVotes) -> (Vec<Vec<usize>>, Vec<usize>, Vec<ItemId>) {\n+    let (_, idx_to_item) = item_index(scope);\n+    let n = idx_to_item.len();\n+    let pairs = voted_pair_indices(scope);\n+    let (comps, isolates) = connected_components_from_voted_pairs(n, pairs.into_iter());\n+    (comps, isolates, idx_to_item)\n+}\n \n-    let mut items: Vec<RankedItem> = group\n-        .idx_to_item\n-        .iter()\n+pub fn ranked_items(scope: &ScopeVotes) -> Vec<RankedItem> {\n+    let (_, idx_to_item) = item_index(scope);\n+    let n = idx_to_item.len();\n+    let edges = edges_from_scope(scope);\n+    let scores = compute_scores_from_edges(n, edges.into_iter(), MAX_ITERS, TOL);\n+\n+    let mut items: Vec<RankedItem> = idx_to_item\n+        .into_iter()\n         .enumerate()\n         .map(|(i, item)| RankedItem {\n-            item: item.clone(),\n+            item,\n             score: *scores.get(i).unwrap_or(&0.0),\n         })\n         .collect();\n@@ -89,11 +155,8 @@ pub fn ranked_items(group: &GroupState) -> Vec<RankedItem> {\n     items\n }\n \n-/// Highest- and lowest-ranked items for a group. Returns up to `k` items from\n-/// each end with no overlap. If the group has `2*k` items or fewer, `top` holds\n-/// the full ranking and `bottom` is empty (so nothing is shown twice).\n-pub fn top_bottom(group: &GroupState, k: usize) -> (Vec<RankedItem>, Vec<RankedItem>) {\n-    let items = ranked_items(group);\n+pub fn top_bottom(scope: &ScopeVotes, k: usize) -> (Vec<RankedItem>, Vec<RankedItem>) {\n+    let items = ranked_items(scope);\n     if k == 0 || items.len() <= 2 * k {\n         return (items, Vec::new());\n     }\n@@ -115,7 +178,6 @@ pub fn compute_scores_from_edges(\n         return vec![1.0];\n     }\n \n-    // Collect raw edges into a map for pairwise normalization.\n     let mut raw: HashMap<(usize, usize), f64> = HashMap::new();\n     for ((src, dst), w) in edges {\n         if src >= n || dst >= n || w <= 0.0 {\n@@ -124,9 +186,6 @@ pub fn compute_scores_from_edges(\n         *raw.entry((src, dst)).or_insert(0.0) += w;\n     }\n \n-    // Pairwise normalization: a_ij = A_ij / (A_ij + A_ji).\n-    // This ensures repeated votes on the same pair don't inflate influence\n-    // beyond what the ratio implies.\n     let keys: Vec<(usize, usize)> = raw.keys().copied().collect();\n     let mut normalized: HashMap<(usize, usize), f64> = HashMap::new();\n     for (i, j) in keys {\n@@ -145,17 +204,6 @@ pub fn compute_scores_from_edges(\n         }\n     }\n \n-    // Rank Centrality (Negahban, Oh, Shah 2012, §3.1):\n-    //   P_ij = (1/d_max) * A_ij           for i ≠ j compared\n-    //   P_ii = 1 - (1/d_max) * Σ_k A_ik\n-    // where d_i is the *degree* (number of distinct neighbors compared) and\n-    // d_max = max_i d_i. Using the unweighted degree — not the sum of\n-    // pairwise-normalized weights — is what guarantees aperiodicity: it\n-    // forces P_ii > 0 for every non-maximum-degree node, and for max-degree\n-    // nodes whenever any neighbor weight is below 1 (i.e. not a unanimous\n-    // loss). Without this, regular comparison graphs (e.g. a pure star at\n-    // ratio 2:1) produce a bipartite chain that oscillates instead of\n-    // converging — see issue #146.\n     let mut out_edges: Vec<Vec<(usize, f64)>> = vec![Vec::new(); n];\n     let mut neighbors: Vec<HashSet<usize>> = vec![HashSet::new(); n];\n \n@@ -213,11 +261,8 @@ pub fn compute_scores_from_edges(\n     scores\n }\n \n-/// Rank-centrality within a subset of items (an induced subgraph), using the group's aggregated edges.\n-///\n-/// `idxs` are indices into `group.idx_to_item`. The returned items use the original item names.\n pub fn ranked_items_subset(\n-    group: &GroupState,\n+    scope: &ScopeVotes,\n     idxs: &[usize],\n     max_iters: usize,\n     tol: f64,\n@@ -226,13 +271,15 @@ pub fn ranked_items_subset(\n         return vec![];\n     }\n \n-    // Map original idx -> compact idx [0..m)\n+    let (_, idx_to_item) = item_index(scope);\n+    let edges = edges_from_scope(scope);\n+\n     let mut map: HashMap<usize, usize> = HashMap::with_capacity(idxs.len());\n     for (j, &i) in idxs.iter().enumerate() {\n         map.insert(i, j);\n     }\n \n-    let edges_iter = group.edges.iter().filter_map(|(&(src, dst), &w)| {\n+    let edges_iter = edges.into_iter().filter_map(|((src, dst), w)| {\n         let s = *map.get(&src)?;\n         let d = *map.get(&dst)?;\n         Some(((s, d), w))\n@@ -240,12 +287,11 @@ pub fn ranked_items_subset(\n \n     let scores = compute_scores_from_edges(idxs.len(), edges_iter, max_iters, tol);\n \n-    // Filter out entries where idx_to_item doesn't have the slot (shouldn't happen, but be safe).\n     let mut items: Vec<RankedItem> = idxs\n         .iter()\n         .enumerate()\n         .filter_map(|(j, &orig)| {\n-            let item = group.idx_to_item.get(orig)?.clone();\n+            let item = idx_to_item.get(orig)?.clone();\n             Some(RankedItem {\n                 item,\n                 score: *scores.get(j).unwrap_or(&0.0),\n@@ -261,8 +307,8 @@ pub fn ranked_items_subset(\n     items\n }\n \n-pub fn group_summary_scores(group: &GroupState) -> HashMap<ItemId, f64> {\n-    ranked_items(group)\n+pub fn group_summary_scores(scope: &ScopeVotes) -> HashMap<ItemId, f64> {\n+    ranked_items(scope)\n         .into_iter()\n         .map(|r| (r.item, r.score))\n         .collect()\n@@ -274,32 +320,26 @@ mod tests {\n     use crate::identity::{DEFAULT_PSEUDONYM, TEST_ACTOR_UUID};\n     use crate::reducer::VoteData;\n \n-    fn mk_group() -> GroupState {\n-        GroupState::new()\n+    fn mk_scope() -> ScopeVotes {\n+        ScopeVotes::default()\n     }\n \n     fn vote(ts: i64, a: &str, b: &str, l: i32, r: i32) -> VoteData {\n         VoteData::from_event(ts, a, b, l, r, DEFAULT_PSEUDONYM.to_string(), 1.0).unwrap()\n     }\n \n-    fn apply(g: &mut GroupState, v: VoteData) {\n-        g.apply_vote(v, TEST_ACTOR_UUID);\n+    fn apply(scope: &mut ScopeVotes, v: VoteData) {\n+        scope.apply_vote(v, TEST_ACTOR_UUID);\n     }\n \n-    /// Regression for issue #146: pure forward star at default `>` ratio (2:1).\n-    /// Under the old (sum-of-weights) divisor every node had P_ii = 0 and the\n-    /// chain was bipartite; power iteration oscillated and returned the\n-    /// uniform initial distribution after an even number of steps. Using the\n-    /// paper's degree-based d_max gives every node a positive self-loop and\n-    /// the chain converges to the correct stationary distribution.\n     #[test]\n     fn star_topology_winner_at_top_via_subset() {\n-        let mut g = mk_group();\n-        g.apply_vote(vote(1, \"zebra\", \"alpha\", 2, 1), TEST_ACTOR_UUID);\n-        g.apply_vote(vote(2, \"zebra\", \"beta\", 2, 1), TEST_ACTOR_UUID);\n+        let mut scope = mk_scope();\n+        apply(&mut scope, vote(1, \"zebra\", \"alpha\", 2, 1));\n+        apply(&mut scope, vote(2, \"zebra\", \"beta\", 2, 1));\n \n-        let mut items: Vec<(usize, String)> = g\n-            .idx_to_item\n+        let (_, idx_to_item) = item_index(&scope);\n+        let mut items: Vec<(usize, String)> = idx_to_item\n             .iter()\n             .enumerate()\n             .map(|(i, it)| (i, it.as_str().to_string()))\n@@ -307,78 +347,51 @@ mod tests {\n         items.sort_by(|a, b| a.1.cmp(&b.1));\n         let idxs: Vec<usize> = items.iter().map(|(i, _)| *i).collect();\n \n-        let ranked = ranked_items_subset(&g, &idxs, 10000, 1e-8);\n-        for r in &ranked {\n-            eprintln!(\"{}: {}\", r.item.as_str(), r.score);\n-        }\n-        assert_eq!(\n-            ranked[0].item.as_str(),\n-            \"zebra\",\n-            \"zebra won both votes and should rank #1\"\n-        );\n+        let ranked = ranked_items_subset(&scope, &idxs, 10000, 1e-8);\n+        assert_eq!(ranked[0].item.as_str(), \"zebra\");\n     }\n \n     #[test]\n     fn top_bottom_splits_ends_without_overlap() {\n-        let mut g = mk_group();\n-        // Chain a > b > c > d > e > f so ranks are well separated.\n+        let mut scope = mk_scope();\n         for (hi, lo) in [(\"a\", \"b\"), (\"b\", \"c\"), (\"c\", \"d\"), (\"d\", \"e\"), (\"e\", \"f\")] {\n-            apply(&mut g, vote(1, hi, lo, 2, 1));\n+            apply(&mut scope, vote(1, hi, lo, 2, 1));\n         }\n-        let (top, bottom) = top_bottom(&g, 2);\n+        let (top, bottom) = top_bottom(&scope, 2);\n         assert_eq!(top.len(), 2);\n         assert_eq!(bottom.len(), 2);\n-        // No overlap between the two ends.\n         for t in &top {\n             assert!(bottom.iter().all(|b| b.item != t.item));\n         }\n-        // Best item ranks above the worst item.\n         assert!(top[0].score >= bottom[bottom.len() - 1].score);\n     }\n \n     #[test]\n     fn top_bottom_small_group_has_empty_bottom() {\n-        let mut g = mk_group();\n-        apply(&mut g, vote(1, \"a\", \"b\", 2, 1));\n-        let (top, bottom) = top_bottom(&g, 5);\n+        let mut scope = mk_scope();\n+        apply(&mut scope, vote(1, \"a\", \"b\", 2, 1));\n+        let (top, bottom) = top_bottom(&scope, 5);\n         assert_eq!(top.len(), 2);\n         assert!(bottom.is_empty());\n     }\n \n     #[test]\n     fn connected_components_split_disconnected_pairs() {\n-        let mut g = mk_group();\n-        // Two disconnected edges: (a,b) and (c,d)\n-        apply(&mut g, vote(1, \"a\", \"b\", 3, 1));\n-        apply(&mut g, vote(2, \"c\", \"d\", 3, 1));\n-\n-        let n = g.idx_to_item.len();\n-        let (mut comps, isolates) =\n-            connected_components_from_voted_pairs(n, g.voted_pairs.iter().copied());\n+        let mut scope = mk_scope();\n+        apply(&mut scope, vote(1, \"a\", \"b\", 3, 1));\n+        apply(&mut scope, vote(2, \"c\", \"d\", 3, 1));\n+\n+        let (_, idx_to_item) = item_index(&scope);\n+        let (mut comps, isolates, _) = scope_components(&scope);\n         assert!(isolates.is_empty());\n-        // Order-independent: sort components by their item names for stable assert.\n         comps.sort_by_key(|c| {\n             c.iter()\n-                .map(|&i| g.idx_to_item[i].clone())\n+                .map(|&i| idx_to_item[i].clone())\n                 .collect::<Vec<_>>()\n         });\n         assert_eq!(comps.len(), 2);\n-        let comp0 = comps[0]\n-            .iter()\n-            .map(|&i| g.idx_to_item[i].as_str())\n-            .collect::<Vec<_>>();\n-        let comp1 = comps[1]\n-            .iter()\n-            .map(|&i| g.idx_to_item[i].as_str())\n-            .collect::<Vec<_>>();\n-        assert_eq!(comp0, vec![\"a\", \"b\"]);\n-        assert_eq!(comp1, vec![\"c\", \"d\"]);\n     }\n \n-    /// A random spanning tree over 26 items needs only n−1 = 25 pairwise votes.\n-    /// When each vote uses the \"perfect\" ratio (strength left : strength right =\n-    /// (idx_left+1) : (idx_right+1)), rank centrality recovers the true order.\n-    /// See `rank-eric.py` (Eric's demo of Negahban–Oh–Shah rank centrality).\n     #[test]\n     fn twenty_five_random_votes_perfect_ratios_sort_alphabet() {\n         use rand::seq::SliceRandom;\n@@ -390,13 +403,13 @@ mod tests {\n         let mut perm: Vec<usize> = (0..N).collect();\n         perm.shuffle(&mut rng);\n \n-        let mut g = mk_group();\n+        let mut scope = mk_scope();\n         for k in 1..N {\n             let i = *perm[..k].choose(&mut rng).unwrap();\n             let j = perm[k];\n             let (a, b) = (letters[i], letters[j]);\n             apply(\n-                &mut g,\n+                &mut scope,\n                 vote(\n                     k as i64,\n                     &a.to_string(),\n@@ -407,34 +420,25 @@ mod tests {\n             );\n         }\n \n-        let ranked = ranked_items(&g);\n+        let ranked = ranked_items(&scope);\n         assert_eq!(ranked.len(), N);\n         for (rank, item) in ranked.iter().enumerate() {\n             let expected = char::from(b'a' + (N - 1 - rank) as u8);\n-            assert_eq!(\n-                item.item.as_str(),\n-                expected.to_string(),\n-                \"rank {rank}: expected '{expected}', got '{}'\",\n-                item.item.as_str()\n-            );\n+            assert_eq!(item.item.as_str(), expected.to_string());\n         }\n     }\n \n     #[test]\n     fn subset_ranking_ranks_within_component_only() {\n-        let mut g = mk_group();\n-        apply(&mut g, vote(1, \"a\", \"b\", 3, 1)); // a > b\n-        apply(&mut g, vote(2, \"c\", \"d\", 1, 4)); // d > c\n-\n-        let (comps, _) = connected_components_from_voted_pairs(\n-            g.idx_to_item.len(),\n-            g.voted_pairs.iter().copied(),\n-        );\n+        let mut scope = mk_scope();\n+        apply(&mut scope, vote(1, \"a\", \"b\", 3, 1));\n+        apply(&mut scope, vote(2, \"c\", \"d\", 1, 4));\n+\n+        let (comps, _, _) = scope_components(&scope);\n         assert_eq!(comps.len(), 2);\n \n-        // Rank each component and ensure winner is first within that component.\n         for comp in comps {\n-            let ranked = ranked_items_subset(&g, &comp, 10000, 1e-8);\n+            let ranked = ranked_items_subset(&scope, &comp, 10000, 1e-8);\n             assert_eq!(ranked.len(), 2);\n             let names = ranked.iter().map(|r| r.item.as_str()).collect::<Vec<_>>();\n             if names.contains(&\"a\") {\ndiff --git a/server/src/reducer.rs b/server/src/reducer.rs\nindex 8c4c9f83635cbcbb037d680dbae2aa99cb2dc785..e6d8c8d2fe763f4928cfbd7c300c8d9768968a3f 100644\n--- a/server/src/reducer.rs\n+++ b/server/src/reducer.rs\n@@ -4,6 +4,24 @@ use serde::{Deserialize, Serialize};\n \n use crate::path_types::ItemId;\n \n+/// `(actor_uuid, min_item_id, max_item_id)` — one vote slot per human per pair.\n+pub type UuidVoteKey = (String, String, String);\n+\n+pub fn canonical_pair_ids(a: &ItemId, b: &ItemId) -> (String, String) {\n+    let ak = a.as_str().to_string();\n+    let bk = b.as_str().to_string();\n+    if ak <= bk {\n+        (ak, bk)\n+    } else {\n+        (bk, ak)\n+    }\n+}\n+\n+pub fn uuid_vote_key(actor_uuid: &str, a: &ItemId, b: &ItemId) -> UuidVoteKey {\n+    let (lo, hi) = canonical_pair_ids(a, b);\n+    (actor_uuid.to_string(), lo, hi)\n+}\n+\n /// Parsed pairwise vote (internal representation).\n #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]\n pub struct VoteData {\n@@ -44,118 +62,20 @@ impl VoteData {\n     }\n }\n \n+/// Votes cast within one ranking scope (parent node). Edges and rankings are\n+/// derived on demand from [`Self::uuid_votes`].\n #[derive(Debug, Clone, Default, Serialize, Deserialize)]\n-pub struct GroupState {\n-    pub item_to_idx: HashMap<ItemId, usize>,\n-    pub idx_to_item: Vec<ItemId>,\n-    pub edges: HashMap<(usize, usize), f64>,\n-    pub voted_pairs: HashSet<(usize, usize)>,\n-    /// Latest vote per `(actor_uuid, min_idx, max_idx)` — Sybil dedup anchor.\n-    pub uuid_votes: HashMap<(String, usize, usize), VoteData>,\n+pub struct ScopeVotes {\n+    pub uuid_votes: HashMap<UuidVoteKey, VoteData>,\n     pub recent_votes: Vec<VoteData>,\n }\n \n-impl GroupState {\n-    pub fn new() -> Self {\n-        Self {\n-            item_to_idx: HashMap::new(),\n-            idx_to_item: Vec::new(),\n-            edges: HashMap::new(),\n-            voted_pairs: HashSet::new(),\n-            uuid_votes: HashMap::new(),\n-            recent_votes: Vec::new(),\n-        }\n-    }\n-\n-    fn ensure_item(&mut self, item: &ItemId) -> usize {\n-        if let Some(&idx) = self.item_to_idx.get(item) {\n-            return idx;\n-        }\n-        let idx = self.idx_to_item.len();\n-        self.idx_to_item.push(item.clone());\n-        self.item_to_idx.insert(item.clone(), idx);\n-        idx\n-    }\n-\n-    fn add_edge_weight(&mut self, src: usize, dst: usize, w: f64) {\n-        if w <= 0.0 {\n-            return;\n-        }\n-        *self.edges.entry((src, dst)).or_insert(0.0) += w;\n-    }\n-\n-    fn subtract_edge_weight(&mut self, src: usize, dst: usize, w: f64) {\n-        if w <= 0.0 {\n-            return;\n-        }\n-        if let Some(entry) = self.edges.get_mut(&(src, dst)) {\n-            *entry -= w;\n-            if *entry <= 0.0 {\n-                self.edges.remove(&(src, dst));\n-            }\n-        }\n-    }\n-\n-    fn apply_weights(&mut self, vote: &VoteData, a_idx: usize, b_idx: usize) {\n-        let w_a = vote.ratio_left as f64 * vote.trust_weight;\n-        let w_b = vote.ratio_right as f64 * vote.trust_weight;\n-        let (i, j) = if a_idx < b_idx {\n-            (a_idx, b_idx)\n-        } else {\n-            (b_idx, a_idx)\n-        };\n-        self.voted_pairs.insert((i, j));\n-        self.add_edge_weight(b_idx, a_idx, w_a);\n-        self.add_edge_weight(a_idx, b_idx, w_b);\n-    }\n-\n-    fn rollback_weights(&mut self, vote: &VoteData) {\n-        let a_idx = match self.item_to_idx.get(&vote.a) {\n-            Some(&i) => i,\n-            None => return,\n-        };\n-        let b_idx = match self.item_to_idx.get(&vote.b) {\n-            Some(&i) => i,\n-            None => return,\n-        };\n-        let w_a = vote.ratio_left as f64 * vote.trust_weight;\n-        let w_b = vote.ratio_right as f64 * vote.trust_weight;\n-        self.subtract_edge_weight(b_idx, a_idx, w_a);\n-        self.subtract_edge_weight(a_idx, b_idx, w_b);\n-    }\n-\n-    /// Apply a validated vote, deduplicating by `actor_uuid` per unordered pair.\n+impl ScopeVotes {\n     pub fn apply_vote(&mut self, vote: VoteData, actor_uuid: &str) {\n-        let a_idx = self.ensure_item(&vote.a);\n-        let b_idx = self.ensure_item(&vote.b);\n-        let (i, j) = if a_idx < b_idx {\n-            (a_idx, b_idx)\n-        } else {\n-            (b_idx, a_idx)\n-        };\n-\n-        let dedupe_key = (actor_uuid.to_string(), i, j);\n-        if let Some(old) = self.uuid_votes.get(&dedupe_key).cloned() {\n-            self.rollback_weights(&old);\n-        }\n-\n-        self.apply_weights(&vote, a_idx, b_idx);\n-        self.uuid_votes.insert(dedupe_key, vote.clone());\n+        let key = uuid_vote_key(actor_uuid, &vote.a, &vote.b);\n+        self.uuid_votes.insert(key, vote.clone());\n         self.recent_votes.push(vote);\n     }\n-\n-    /// Rebuild edge weights from deduped uuid votes (load path — no rollback).\n-    pub fn ingest_uuid_vote(&mut self, vote: VoteData, actor_uuid: &str) {\n-        let a_idx = self.ensure_item(&vote.a);\n-        let b_idx = self.ensure_item(&vote.b);\n-        let (i, j) = if a_idx < b_idx {\n-            (a_idx, b_idx)\n-        } else {\n-            (b_idx, a_idx)\n-        };\n-        self.apply_weights(&vote, a_idx, b_idx);\n-        self.uuid_votes.insert((actor_uuid.to_string(), i, j), vote);\n-    }\n }\n \n /// Structured data imported from Reddit or elsewhere.\n@@ -179,7 +99,7 @@ pub struct NodeState {\n     /// Ephemeral display view (Reddit title/author/etc.; not event-logged).\n     pub data: Option<EntityData>,\n     pub children: HashSet<ItemId>,\n-    pub local_ranking: GroupState,\n+    pub votes: ScopeVotes,\n }\n \n impl NodeState {\n@@ -242,7 +162,7 @@ impl GlobalTree {\n         if let Some(node) = self.nodes.get_mut(parent) {\n             node.children.insert(vote.a.clone());\n             node.children.insert(vote.b.clone());\n-            node.local_ranking.apply_vote(vote, actor_uuid);\n+            node.votes.apply_vote(vote, actor_uuid);\n         }\n     }\n \n@@ -276,6 +196,7 @@ impl GlobalTree {\n #[cfg(test)]\n mod tests {\n     use super::*;\n+    use crate::ranking::edge_weight_sum;\n \n     fn vote(ts: i64, a: &str, b: &str, l: i32, r: i32, pseudonym: &str) -> VoteData {\n         VoteData {\n@@ -310,26 +231,23 @@ mod tests {\n \n     #[test]\n     fn same_uuid_replaces_prior_vote_on_pair() {\n-        let mut g = GroupState::new();\n+        let mut scope = ScopeVotes::default();\n         let uuid = \"u1\";\n-        g.apply_vote(vote(1, \"a\", \"b\", 2, 1, \"alice\"), uuid);\n-        let first_total: f64 = g.edges.values().sum();\n-        assert_eq!(first_total, 3.0);\n+        scope.apply_vote(vote(1, \"a\", \"b\", 2, 1, \"alice\"), uuid);\n+        assert_eq!(edge_weight_sum(&scope), 3.0);\n \n-        g.apply_vote(vote(2, \"a\", \"b\", 0, 1, \"bob\"), uuid);\n-        let second_total: f64 = g.edges.values().sum();\n-        assert_eq!(second_total, 1.0);\n-        assert_eq!(g.uuid_votes.len(), 1);\n+        scope.apply_vote(vote(2, \"a\", \"b\", 0, 1, \"bob\"), uuid);\n+        assert_eq!(edge_weight_sum(&scope), 1.0);\n+        assert_eq!(scope.uuid_votes.len(), 1);\n     }\n \n     #[test]\n     fn different_uuids_both_count() {\n-        let mut g = GroupState::new();\n-        g.apply_vote(vote(1, \"a\", \"b\", 2, 1, \"alice\"), \"u1\");\n-        g.apply_vote(vote(2, \"a\", \"b\", 0, 1, \"bob\"), \"u2\");\n-        let total: f64 = g.edges.values().sum();\n-        assert_eq!(total, 4.0);\n-        assert_eq!(g.uuid_votes.len(), 2);\n+        let mut scope = ScopeVotes::default();\n+        scope.apply_vote(vote(1, \"a\", \"b\", 2, 1, \"alice\"), \"u1\");\n+        scope.apply_vote(vote(2, \"a\", \"b\", 0, 1, \"bob\"), \"u2\");\n+        assert_eq!(edge_weight_sum(&scope), 4.0);\n+        assert_eq!(scope.uuid_votes.len(), 2);\n     }\n \n     #[test]\ndiff --git a/server/src/state.rs b/server/src/state.rs\nindex 8dabc93e95c39cbe18d69596dee79683b384ef86..dcb82ff4beeaac8f0820de0e0131ca1f6bd81dcc 100644\n--- a/server/src/state.rs\n+++ b/server/src/state.rs\n@@ -269,7 +269,7 @@ mod tests {\n     use super::{normalize_scope, parse_item_param, AppConfig, AppState};\n     use crate::{\n         event_log::EventLog, events::Event, path_types::ItemId, projection_apply,\n-        projection_store::ProjectionStore, reducer::EntityData,\n+        projection_store::ProjectionStore, ranking::edge_weight_sum, reducer::EntityData,\n     };\n \n     fn event_record(seq: u64, event: Event) -> crate::events::EventRecord {\n@@ -442,7 +442,7 @@ mod tests {\n         assert_eq!(projection_store.last_applied_event_count().unwrap(), 1);\n         let first = projection_store.scope_tree(&ItemId::root()).unwrap();\n         let first_root = first.get(&ItemId::root()).unwrap();\n-        let first_edge_total: f64 = first_root.local_ranking.edges.values().sum();\n+        let first_edge_total = edge_weight_sum(&first_root.votes);\n         assert_eq!(first_edge_total, 3.0);\n \n         super::catch_up_projection(&log, &projection_store)\n@@ -451,7 +451,7 @@ mod tests {\n         assert_eq!(projection_store.last_applied_event_count().unwrap(), 1);\n         let second = projection_store.scope_tree(&ItemId::root()).unwrap();\n         let second_root = second.get(&ItemId::root()).unwrap();\n-        let second_edge_total: f64 = second_root.local_ranking.edges.values().sum();\n+        let second_edge_total = edge_weight_sum(&second_root.votes);\n         assert_eq!(second_edge_total, first_edge_total);\n     }\n \n@@ -529,9 +529,8 @@ mod tests {\n         let root = projected.get(&ItemId::root()).unwrap();\n         assert!(root.children.contains(&ItemId::parse(\"alpha\").unwrap()));\n         assert!(root.children.contains(&ItemId::parse(\"beta\").unwrap()));\n-        assert_eq!(root.local_ranking.idx_to_item.len(), 2);\n-        let edge_total: f64 = root.local_ranking.edges.values().sum();\n-        assert_eq!(edge_total, 3.0);\n+        assert_eq!(crate::ranking::ranked_items(&root.votes).len(), 2);\n+        assert_eq!(edge_weight_sum(&root.votes), 3.0);\n     }\n \n     #[tokio::test]\n@@ -620,7 +619,7 @@ mod tests {\n         let root = tree.get(&ItemId::root()).unwrap();\n         assert!(root.children.contains(&ItemId::parse(\"beta\").unwrap()));\n         assert!(root.children.contains(&ItemId::parse(\"gamma\").unwrap()));\n-        assert_eq!(root.local_ranking.idx_to_item.len(), 3);\n+        assert_eq!(crate::ranking::ranked_items(&root.votes).len(), 3);\n     }\n \n     #[test]\ndiff --git a/server/src/storage_schema.rs b/server/src/storage_schema.rs\nindex 67c9f4ab2e1865f8da81b6735dd2a05b87e5e366..fe2671b876f3df77fdfd402dbc845ff1eb3512cd 100644\n--- a/server/src/storage_schema.rs\n+++ b/server/src/storage_schema.rs\n@@ -3,86 +3,53 @@\n //!\n //! Votes are stored as deduped `uuid_votes` entries plus an append-only\n //! `recent_votes` audit list. Edge weights for rank centrality are derived\n-//! from `uuid_votes` on read, not incrementally merged in RocksDB.\n+//! from `uuid_votes` on read, not stored in RocksDB.\n \n-use std::collections::{HashSet};\n+use std::collections::HashSet;\n \n use durable::{Batch, Db, Durable, Leaf, List, Map};\n \n use crate::{\n     path_types::ItemId,\n-    reducer::{EntityData, GroupState, NodeState, VoteData},\n+    reducer::{EntityData, NodeState, ScopeVotes, VoteData, UuidVoteKey, uuid_vote_key},\n     storage_dto::{\n         decode_entity_data, decode_vote, encode_entity_data, encode_vote, parse_stored_id,\n         StoredEntityDataV1, StoredVoteV1,\n     },\n };\n \n-/// `(actor_uuid, min_item_id, max_item_id)` — one vote slot per human per pair.\n-pub type UuidVoteKey = (String, String, String);\n-\n /// One node in the fractal tree, exploded into precisely-updatable collections.\n #[derive(Durable)]\n #[allow(dead_code)]\n pub struct NodeSchema {\n-    /// Presence marker (a node \"exists\" once ensured/voted/imported).\n     pub present: Leaf<bool>,\n-    /// Domain-specific derived view (Reddit title/author/…); absent => None.\n     pub data: Leaf<StoredEntityDataV1>,\n-    /// Child ids (a set; value is always `true`).\n     pub children: Map<String, Leaf<bool>>,\n-    /// Latest vote per actor per unordered pair; edges are derived from this on read.\n     pub uuid_votes: Map<UuidVoteKey, Leaf<StoredVoteV1>>,\n-    /// Recent votes, append-only oldest-first (cap applied on read).\n     pub recent_votes: List<Leaf<StoredVoteV1>>,\n-    /// When ephemeral Reddit display content was last fetched (ms); absent after eviction.\n     pub fetched_at: Leaf<i64>,\n }\n \n-/// The single database root: nodes, identity maps, view counts, and metadata.\n #[derive(Durable)]\n #[allow(dead_code)]\n pub struct Store {\n     pub nodes: Map<String, NodeSchema>,\n-    /// Global pseudonym → actor UUID (Sybil dedup anchor).\n     pub pseudonyms: Map<String, Leaf<String>>,\n     pub proj_meta: Map<String, Leaf<u64>>,\n     pub view_counts: Map<String, Leaf<u64>>,\n     pub view_meta: Map<String, Leaf<u64>>,\n }\n \n-/// Max recent votes returned when loading a node (query-time cap only).\n pub const RECENT_VOTES_CAP: u64 = 200;\n \n fn id_key(id: &ItemId) -> String {\n     id.as_str().to_string()\n }\n \n-fn pair_keys(a: &ItemId, b: &ItemId) -> (String, String) {\n-    let ak = id_key(a);\n-    let bk = id_key(b);\n-    if ak <= bk {\n-        (ak, bk)\n-    } else {\n-        (bk, ak)\n-    }\n-}\n-\n-pub fn uuid_vote_key(actor_uuid: &str, a: &ItemId, b: &ItemId) -> UuidVoteKey {\n-    let (lo, hi) = pair_keys(a, b);\n-    (actor_uuid.to_string(), lo, hi)\n-}\n-\n-/// Path to a node by id.\n pub fn node(id: &ItemId) -> durable::Path<NodeSchema> {\n     Store::root().nodes().key(&id_key(id))\n }\n \n-// ---------------------------------------------------------------------------\n-// Reconstruction (durable -> in-memory)\n-// ---------------------------------------------------------------------------\n-\n-/// Reconstruct a node's in-memory state, or `None` if the node does not exist.\n pub fn load_node_state(db: &Db, id: &ItemId) -> durable::Result<Option<NodeState>> {\n     let np = node(id);\n     let present = np.present().get(db)?.unwrap_or(false);\n@@ -100,47 +67,39 @@ pub fn load_node_state(db: &Db, id: &ItemId) -> durable::Result<Option<NodeState\n         children.insert(parse_storage_id(&child)?);\n     }\n \n-    let local_ranking = build_group_state(db, &np)?;\n+    let votes = load_scope_votes(db, &np)?;\n \n     Ok(Some(NodeState {\n         id: id.clone(),\n         data: data.map(decode_entity_data),\n         children,\n-        local_ranking,\n+        votes,\n     }))\n }\n \n-fn build_group_state(db: &Db, np: &durable::Path<NodeSchema>) -> durable::Result<GroupState> {\n-    let mut group = GroupState::new();\n+fn load_scope_votes(db: &Db, np: &durable::Path<NodeSchema>) -> durable::Result<ScopeVotes> {\n+    let mut votes = ScopeVotes::default();\n \n     for (key, stored) in np.uuid_votes().iter(db)? {\n-        let (actor_uuid, _lo, _hi) = key;\n         let vote = decode_vote(stored).map_err(durable::Error::Deserialize)?;\n-        group.ingest_uuid_vote(vote, &actor_uuid);\n+        votes.uuid_votes.insert(key, vote);\n     }\n \n     let stored = np.recent_votes().iter(db)?;\n     let cap = RECENT_VOTES_CAP as usize;\n     let start = stored.len().saturating_sub(cap);\n-    group.recent_votes = stored[start..]\n+    votes.recent_votes = stored[start..]\n         .iter()\n         .map(|s| decode_vote(s.clone()).map_err(durable::Error::Deserialize))\n         .collect::<Result<Vec<_>, _>>()?;\n \n-    Ok(group)\n+    Ok(votes)\n }\n \n fn parse_storage_id(s: &str) -> durable::Result<ItemId> {\n     parse_stored_id(s).map_err(durable::Error::Deserialize)\n }\n \n-// ---------------------------------------------------------------------------\n-// Write helpers (event -> reified point updates on a batch)\n-// ---------------------------------------------------------------------------\n-\n-/// Wire a node and its ancestors into the tree exactly like\n-/// [`crate::reducer::GlobalTree::ensure_path`]: set presence and parent→child\n-/// links along the canonical breadcrumb path.\n pub fn ensure_path_writes(batch: &mut Batch, id: &ItemId) {\n     let root = ItemId::root();\n     batch.write(node(&root).present().set(&true));\n@@ -161,7 +120,6 @@ pub fn ensure_path_writes(batch: &mut Batch, id: &ItemId) {\n     }\n }\n \n-/// Reified writes for a validated vote under `parent`.\n pub fn vote_writes(\n     batch: &mut Batch,\n     parent: &ItemId,\n@@ -182,14 +140,12 @@ pub fn vote_writes(\n     Ok(())\n }\n \n-/// Reified writes for ephemeral Reddit display content (not event-logged).\n pub fn entity_content_writes(batch: &mut Batch, id: &ItemId, view: &EntityData, fetched_at: i64) {\n     ensure_path_writes(batch, id);\n     batch.write(node(id).data().set(&encode_entity_data(view)));\n     batch.write(node(id).fetched_at().set(&fetched_at));\n }\n \n-/// Clear cached display content for one node (structure/votes are untouched).\n pub fn entity_content_clear_writes(batch: &mut Batch, id: &ItemId) {\n     batch.write(node(id).data().delete());\n     batch.write(node(id).fetched_at().delete());\n@@ -199,6 +155,7 @@ pub fn entity_content_clear_writes(batch: &mut Batch, id: &ItemId) {\n mod tests {\n     use super::*;\n     use crate::identity::{seed_default_pseudonym, DEFAULT_ACTOR_UUID, DEFAULT_PSEUDONYM};\n+    use crate::ranking::edge_weight_sum;\n \n     fn sample_vote(ts: i64, a: &str, b: &str, l: i32, r: i32) -> VoteData {\n         VoteData {\n@@ -213,7 +170,7 @@ mod tests {\n     }\n \n     #[test]\n-    fn vote_roundtrip_reconstructs_group_state() {\n+    fn vote_roundtrip_reconstructs_ranking() {\n         let dir = tempfile::tempdir().unwrap();\n         let db = Db::open(dir.path()).unwrap();\n         seed_default_pseudonym(&db).unwrap();\n@@ -225,11 +182,8 @@ mod tests {\n         batch.commit().unwrap();\n \n         let node_state = load_node_state(&db, &parent).unwrap().unwrap();\n-        let g = &node_state.local_ranking;\n-        assert_eq!(g.idx_to_item.len(), 2);\n-        let edge_total: f64 = g.edges.values().sum();\n-        assert_eq!(edge_total, 3.0);\n-        assert_eq!(g.recent_votes.len(), 1);\n+        assert_eq!(edge_weight_sum(&node_state.votes), 3.0);\n+        assert_eq!(node_state.votes.recent_votes.len(), 1);\n         assert!(node_state.children.contains(&ItemId::opaque(\"alpha\")));\n         assert!(node_state.children.contains(&ItemId::opaque(\"beta\")));\n     }\n@@ -263,10 +217,9 @@ mod tests {\n         .unwrap();\n         batch.commit().unwrap();\n \n-        let g = &load_node_state(&db, &parent).unwrap().unwrap().local_ranking;\n-        let edge_total: f64 = g.edges.values().sum();\n-        assert_eq!(edge_total, 1.0);\n-        assert_eq!(g.uuid_votes.len(), 1);\n+        let votes = &load_node_state(&db, &parent).unwrap().unwrap().votes;\n+        assert_eq!(edge_weight_sum(votes), 1.0);\n+        assert_eq!(votes.uuid_votes.len(), 1);\n     }\n \n     #[test]\n@@ -293,15 +246,8 @@ mod tests {\n         );\n \n         let node_state = load_node_state(&db, &parent).unwrap().unwrap();\n-        assert_eq!(node_state.local_ranking.recent_votes.len(), RECENT_VOTES_CAP as usize);\n-        assert_eq!(\n-            node_state\n-                .local_ranking\n-                .recent_votes\n-                .first()\n-                .map(|v| v.ts),\n-            Some(10)\n-        );\n+        assert_eq!(node_state.votes.recent_votes.len(), RECENT_VOTES_CAP as usize);\n+        assert_eq!(node_state.votes.recent_votes.first().map(|v| v.ts), Some(10));\n     }\n \n     #[test]\ndiff --git a/server/tests/integration_ui.rs b/server/tests/integration_ui.rs\nindex cc7a16d756673b95ba336f2d6130eaf40908cc60..40e4cfe1eec36dad29a075fb01aefb4dffd856d0 100644\n--- a/server/tests/integration_ui.rs\n+++ b/server/tests/integration_ui.rs\n@@ -132,7 +132,7 @@ async fn post_ui_record_vote_morphs_ranking_and_persists() {\n     let state = create_app_state(cfg).await;\n     let tree = state.scope_tree(&ItemId::root()).unwrap();\n     let root = tree.get(&ItemId::root()).expect(\"root node after replay\");\n-    let ranked = sorter2_server::ranking::ranked_items(&root.local_ranking);\n+    let ranked = sorter2_server::ranking::ranked_items(&root.votes);\n     assert_eq!(ranked.len(), 2);\n     assert_eq!(ranked[0].item.as_str(), \"alpha\");\n }\n\n\nSide B — contributor: tommy-mor\nSide B — commit message:\n[15e1037a] url stuff\n\nSide B — unified diff (full patch):\ndiff --git a/server/src/url_rules/graph.rs b/server/src/url_rules/graph.rs\nnew file mode 100644\nindex 0000000000000000000000000000000000000000..f7ac0f9a551a1727cb2f9294778c283b9885b147\n--- /dev/null\n+++ b/server/src/url_rules/graph.rs\n@@ -0,0 +1,831 @@\n+//! Semantic URL graph: DFA traversal on host + path, query in context, generic fallback.\n+\n+use std::collections::HashMap;\n+use std::sync::OnceLock;\n+\n+use url::Url;\n+\n+use super::graph_builder::GraphBuilder;\n+use super::parse::{normalize_match_host, strip_tracking_query, UrlParts};\n+\n+#[derive(Debug, Clone, Default)]\n+pub struct Context {\n+    pub vars: HashMap<String, String>,\n+    pub query: HashMap<String, String>,\n+}\n+\n+pub type CanonicalFn = fn(&Context) -> Option<String>;\n+\n+#[derive(Clone, Copy)]\n+pub enum EdgePattern {\n+    Literal(&'static str),\n+    Variable(&'static str),\n+    /// Absorb any trailing segment without leaving this node (e.g. post title slug).\n+    AbsorbAny,\n+    /// Absorb segment when `cond(seg)` (e.g. subreddit listing suffix).\n+    AbsorbIf(fn(&str) -> bool),\n+}\n+\n+pub struct Edge {\n+    pub pattern: EdgePattern,\n+    pub target: &'static str,\n+}\n+\n+pub struct Node {\n+    pub edges: Vec<Edge>,\n+    pub canonical: CanonicalFn,\n+    pub parent: Option<&'static str>,\n+}\n+\n+impl Node {\n+    pub(crate) fn empty() -> Self {\n+        Self {\n+            edges: Vec::new(),\n+            canonical: |_| None,\n+            parent: None,\n+        }\n+    }\n+}\n+\n+pub struct Graph {\n+    pub nodes: HashMap<&'static str, Node>,\n+}\n+\n+static GRAPH: OnceLock<Graph> = OnceLock::new();\n+\n+pub fn graph() -> &'static Graph {\n+    GRAPH.get_or_init(build_graph)\n+}\n+\n+impl Graph {\n+    pub fn resolve_canonical(&self, parts: &UrlParts) -> Option<String> {\n+        let mut query = parts.query.clone();\n+        strip_tracking_query(&mut query);\n+        let mut ctx = Context {\n+            vars: HashMap::new(),\n+            query,\n+        };\n+\n+        if let Some(node_id) = self.traverse(parts, &mut ctx) {\n+            if let Some(canon) = (self.nodes.get(node_id)?.canonical)(&ctx) {\n+                return Some(canon);\n+            }\n+        }\n+        Some(generic_canonical(parts))\n+    }\n+\n+    pub fn breadcrumbs(&self, parts: &UrlParts) -> Vec<String> {\n+        let mut query = parts.query.clone();\n+        strip_tracking_query(&mut query);\n+        let mut ctx = Context {\n+            vars: HashMap::new(),\n+            query,\n+        };\n+\n+        if let Some(mut node_id) = self.traverse(parts, &mut ctx) {\n+            let mut paths = Vec::new();\n+            loop {\n+                let node = match self.nodes.get(node_id) {\n+                    Some(n) => n,\n+                    None => break,\n+                };\n+                if let Some(url) = (node.canonical)(&ctx) {\n+                    if paths.last() != Some(&url) {\n+                        paths.push(url);\n+                    }\n+                }\n+                match node.parent {\n+                    Some(p) => node_id = p,\n+                    None => break,\n+                }\n+            }\n+            paths.reverse();\n+            if !paths.is_empty() {\n+                return paths;\n+            }\n+        }\n+        generic_breadcrumbs(parts)\n+    }\n+\n+    fn traverse(&self, parts: &UrlParts, ctx: &mut Context) -> Option<&'static str> {\n+        let host = parts.match_host();\n+        let mut node_id = match host.as_str() {\n+            \"reddit.com\" => \"reddit_root\",\n+            \"youtube.com\" => \"youtube_root\",\n+            \"youtu.be\" => \"youtu_be_entry\",\n+            _ => return None,\n+        };\n+\n+        let segs: Vec<&str> = parts.path_segments.iter().map(String::as_str).collect();\n+        let mut i = 0;\n+        while i < segs.len() {\n+            let seg = segs[i];\n+            match self.follow_edge(node_id, seg, ctx) {\n+                Ok(next) => {\n+                    node_id = next;\n+                    i += 1;\n+                }\n+                Err(()) => {\n+                    if self.try_absorb(node_id, seg) {\n+                        i += 1;\n+                        continue;\n+                    }\n+                    return None;\n+                }\n+            }\n+        }\n+        Some(node_id)\n+    }\n+\n+    fn follow_edge(\n+        &self,\n+        node_id: &'static str,\n+        seg: &str,\n+        ctx: &mut Context,\n+    ) -> Result<&'static str, ()> {\n+        let node = self.nodes.get(node_id).ok_or(())?;\n+        for edge in &node.edges {\n+            match edge.pattern {\n+                EdgePattern::Literal(lit) if lit == seg => return Ok(edge.target),\n+                EdgePattern::Variable(name) => {\n+                    ctx.vars.insert(name.to_string(), seg.to_string());\n+                    return Ok(edge.target);\n+                }\n+                EdgePattern::AbsorbAny\n+                | EdgePattern::AbsorbIf(_)\n+                | EdgePattern::Literal(_)\n+                | EdgePattern::Variable(_) => {}\n+            }\n+        }\n+        Err(())\n+    }\n+\n+    fn try_absorb(&self, node_id: &'static str, seg: &str) -> bool {\n+        let node = match self.nodes.get(node_id) {\n+            Some(n) => n,\n+            None => return false,\n+        };\n+        for edge in &node.edges {\n+            match edge.pattern {\n+                EdgePattern::AbsorbAny => return true,\n+                EdgePattern::AbsorbIf(cond) if cond(seg) => return true,\n+                EdgePattern::AbsorbIf(_) | EdgePattern::Literal(_) | EdgePattern::Variable(_) => {}\n+            }\n+        }\n+        false\n+    }\n+\n+    /// Test hook: terminal graph node and captured context after traversal.\n+    #[cfg(test)]\n+    pub fn traverse_terminal(&self, parts: &UrlParts) -> Option<(&'static str, Context)> {\n+        let mut query = parts.query.clone();\n+        strip_tracking_query(&mut query);\n+        let mut ctx = Context {\n+            vars: HashMap::new(),\n+            query,\n+        };\n+        let node = self.traverse(parts, &mut ctx)?;\n+        Some((node, ctx))\n+    }\n+}\n+\n+fn is_reddit_listing_suffix(seg: &str) -> bool {\n+    matches!(seg, \"hot\" | \"top\" | \"new\" | \"rising\" | \"controversial\")\n+}\n+\n+/// Percent-encode a path or query fragment so `&`, `?`, etc. cannot break URL structure.\n+fn enc(s: &str) -> String {\n+    urlencoding::encode(s).into_owned()\n+}\n+\n+// --- Canonical formatters ---\n+\n+fn canon_reddit_root(_: &Context) -> Option<String> {\n+    Some(\"https://reddit.com\".to_string())\n+}\n+\n+fn canon_reddit_r_hub(_: &Context) -> Option<String> {\n+    Some(\"https://reddit.com/r\".to_string())\n+}\n+\n+fn canon_reddit_subreddit(ctx: &Context) -> Option<String> {\n+    let sub = ctx.vars.get(\"subreddit\")?;\n+    Some(format!(\n+        \"https://reddit.com/r/{}\",\n+        enc(&sub.to_ascii_lowercase())\n+    ))\n+}\n+\n+fn canon_reddit_post(ctx: &Context) -> Option<String> {\n+    let sub = ctx.vars.get(\"subreddit\")?.to_ascii_lowercase();\n+    let id = ctx.vars.get(\"post_id\")?;\n+    Some(format!(\n+        \"https://reddit.com/r/{}/comments/{}\",\n+        enc(&sub),\n+        enc(id)\n+    ))\n+}\n+\n+fn canon_youtube_root(_: &Context) -> Option<String> {\n+    Some(\"https://youtube.com\".to_string())\n+}\n+\n+fn canon_youtube_watch(ctx: &Context) -> Option<String> {\n+    let v = ctx\n+        .query\n+        .get(\"v\")\n+        .or_else(|| ctx.vars.get(\"video_id\"))?;\n+    Some(format!(\"https://youtube.com/watch?v={}\", enc(v)))\n+}\n+\n+fn canon_youtu_be(ctx: &Context) -> Option<String> {\n+    let v = ctx.vars.get(\"vid_id\")?;\n+    Some(format!(\"https://youtube.com/watch?v={}\", enc(v)))\n+}\n+\n+pub fn build_graph() -> Graph {\n+    GraphBuilder::new()\n+        .node(\"reddit_root\")\n+        .canonical(canon_reddit_root)\n+        .edge(EdgePattern::Literal(\"r\"), \"reddit_r_hub\")\n+        .node(\"reddit_r_hub\")\n+        .parent(\"reddit_root\")\n+        .canonical(canon_reddit_r_hub)\n+        .edge(EdgePattern::Variable(\"subreddit\"), \"reddit_subreddit\")\n+        .node(\"reddit_subreddit\")\n+        .parent(\"reddit_r_hub\")\n+        .canonical(canon_reddit_subreddit)\n+        .edge(\n+            EdgePattern::AbsorbIf(is_reddit_listing_suffix),\n+            \"reddit_subreddit\",\n+        )\n+        .edge(EdgePattern::Literal(\"comments\"), \"reddit_comments_gate\")\n+        .node(\"reddit_comments_gate\")\n+        .parent(\"reddit_subreddit\")\n+        .canonical(canon_reddit_subreddit)\n+        .edge(EdgePattern::Variable(\"post_id\"), \"reddit_post\")\n+        .node(\"reddit_post\")\n+        .parent(\"reddit_subreddit\")\n+        .canonical(canon_reddit_post)\n+        .edge(EdgePattern::AbsorbAny, \"reddit_post\")\n+        .node(\"youtube_root\")\n+        .canonical(canon_youtube_root)\n+        .edge(EdgePattern::Literal(\"watch\"), \"youtube_watch\")\n+        .edge(EdgePattern::Literal(\"shorts\"), \"youtube_shorts_gate\")\n+        .node(\"youtube_watch\")\n+        .parent(\"youtube_root\")\n+        .canonical(canon_youtube_watch)\n+        .node(\"youtube_shorts_gate\")\n+        .parent(\"youtube_root\")\n+        .canonical(canon_youtube_root)\n+        .edge(EdgePattern::Variable(\"video_id\"), \"youtube_watch\")\n+        .node(\"youtu_be_entry\")\n+        .canonical(canon_youtube_root)\n+        .edge(EdgePattern::Variable(\"vid_id\"), \"youtu_be_video\")\n+        .node(\"youtu_be_video\")\n+        .parent(\"youtube_root\")\n+        .canonical(canon_youtu_be)\n+        .build()\n+}\n+\n+// --- Generic internet fallback ---\n+\n+pub fn generic_canonical(parts: &UrlParts) -> String {\n+    let host = normalize_match_host(&parts.host);\n+    let path_segments: Vec<String> = parts.path_segments.clone();\n+    let mut query = parts.query.clone();\n+    strip_tracking_query(&mut query);\n+\n+    let mut url = if path_segments.is_empty() {\n+        Url::parse(&format!(\"https://{host}\"))\n+            .unwrap_or_else(|_| Url::parse(\"https://invalid\").unwrap())\n+    } else {\n+        let path = format!(\"/{}\", path_segments.join(\"/\"));\n+        Url::parse(&format!(\"https://{host}{path}\"))\n+            .unwrap_or_else(|_| Url::parse(\"https://invalid\").unwrap())\n+    };\n+\n+    if !query.is_empty() {\n+        let mut pairs: Vec<_> = query.iter().collect();\n+        pairs.sort_by(|a, b| a.0.cmp(b.0));\n+        url.query_pairs_mut().clear();\n+        for (k, v) in pairs {\n+            url.query_pairs_mut().append_pair(k, v);\n+        }\n+    }\n+\n+    let mut s = url.to_string();\n+    if path_segments.is_empty() {\n+        s = s.trim_end_matches('/').to_string();\n+    }\n+    s\n+}\n+\n+pub fn generic_breadcrumbs(parts: &UrlParts) -> Vec<String> {\n+    let host = normalize_match_host(&parts.host);\n+    let n = parts.path_segments.len();\n+    let mut out = Vec::new();\n+\n+    let base = generic_canonical(&UrlParts {\n+        scheme: \"https\".to_string(),\n+        host: host.clone(),\n+        path_segments: vec![],\n+        query: HashMap::new(),\n+    });\n+    out.push(base);\n+\n+    for i in 0..n {\n+        let segs: Vec<String> = parts.path_segments[..=i].to_vec();\n+        let url = generic_canonical(&UrlParts {\n+            scheme: \"https\".to_string(),\n+            host: host.clone(),\n+            path_segments: segs,\n+            query: HashMap::new(),\n+        });\n+        if out.last() != Some(&url) {\n+            out.push(url);\n+        }\n+    }\n+    out\n+}\n+\n+#[cfg(test)]\n+mod tests {\n+    use super::*;\n+    use crate::url_rules::parse::test_parts;\n+\n+    fn g() -> &'static Graph {\n+        graph()\n+    }\n+\n+    fn canon(parts: &UrlParts) -> String {\n+        g().resolve_canonical(parts).unwrap()\n+    }\n+\n+    fn crumbs(parts: &UrlParts) -> Vec<String> {\n+        g().breadcrumbs(parts)\n+    }\n+\n+    fn terminal(parts: &UrlParts) -> Option<&'static str> {\n+        g().traverse_terminal(parts).map(|(n, _)| n)\n+    }\n+\n+    fn vars(parts: &UrlParts) -> HashMap<String, String> {\n+        g().traverse_terminal(parts)\n+            .map(|(_, c)| c.vars)\n+            .unwrap_or_default()\n+    }\n+\n+    #[test]\n+    fn youtu_be_malicious_segment_encoded_not_injected() {\n+        let p = test_parts(\"youtu.be\", &[\"abc&t=1\"], &[]);\n+        assert_eq!(canon(&p), \"https://youtube.com/watch?v=abc%26t%3D1\");\n+        assert!(!canon(&p).contains(\"abc&t=1\"));\n+    }\n+\n+    #[test]\n+    fn youtube_query_v_encoded() {\n+        let p = test_parts(\"youtube.com\", &[\"watch\"], &[(\"v\", \"a&b=c\")]);\n+        assert_eq!(canon(&p), \"https://youtube.com/watch?v=a%26b%3Dc\");\n+    }\n+\n+    #[test]\n+    fn absorb_patterns_live_on_edges_not_in_engine() {\n+        let g = build_graph();\n+        let sub = g.nodes.get(\"reddit_subreddit\").unwrap();\n+        assert!(sub\n+            .edges\n+            .iter()\n+            .any(|e| matches!(e.pattern, EdgePattern::AbsorbIf(_))));\n+        let post = g.nodes.get(\"reddit_post\").unwrap();\n+        assert!(post\n+            .edges\n+            .iter()\n+            .any(|e| matches!(e.pattern, EdgePattern::AbsorbAny)));\n+    }\n+\n+    #[test]\n+    fn builder_rejects_missing_parent() {\n+        let result = std::panic::catch_unwind(|| {\n+            GraphBuilder::new()\n+                .node(\"orphan\")\n+                .parent(\"nonexistent_parent\")\n+                .build();\n+        });\n+        assert!(result.is_err());\n+    }\n+\n+    #[test]\n+    fn generic_canonical_forces_https_and_strips_www() {\n+        let p = test_parts(\"www.example.com\", &[\"blog\", \"post\"], &[]);\n+        assert_eq!(canon(&p), \"https://example.com/blog/post\");\n+    }\n+\n+    #[test]\n+    fn generic_canonical_sorts_query_keys() {\n+        let p = test_parts(\"example.com\", &[\"search\"], &[(\"q\", \"rust\"), (\"page\", \"2\")]);\n+        assert_eq!(canon(&p), \"https://example.com/search?page=2&q=rust\");\n+    }\n+\n+    #[test]\n+    fn generic_canonical_strips_tracking_from_query() {\n+        let p = test_parts(\n+            \"news.ycombinator.com\",\n+            &[\"item\"],\n+            &[(\"id\", \"1\"), (\"utm_medium\", \"social\")],\n+        );\n+        assert_eq!(canon(&p), \"https://news.ycombinator.com/item?id=1\");\n+    }\n+\n+    #[test]\n+    fn generic_breadcrumbs_cumulative_path() {\n+        let p = test_parts(\"paulgraham.com\", &[\"articles\", \"lisp.html\"], &[]);\n+        assert_eq!(\n+            crumbs(&p),\n+            vec![\n+                \"https://paulgraham.com\",\n+                \"https://paulgraham.com/articles\",\n+                \"https://paulgraham.com/articles/lisp.html\"\n+            ]\n+        );\n+    }\n+\n+    #[test]\n+    fn generic_breadcrumbs_domain_only() {\n+        let p = test_parts(\"example.com\", &[], &[]);\n+        assert_eq!(crumbs(&p), vec![\"https://example.com\"]);\n+    }\n+\n+    #[test]\n+    fn unknown_host_uses_generic_not_graph() {\n+        let p = test_parts(\"hackernews.com\", &[\"item\", \"123\"], &[]);\n+        assert_eq!(terminal(&p), None);\n+        assert_eq!(canon(&p), \"https://hackernews.com/item/123\");\n+    }\n+\n+    #[test]\n+    fn traverse_captures_subreddit_variable() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"Rust\"], &[]);\n+        assert_eq!(terminal(&p), Some(\"reddit_subreddit\"));\n+        assert_eq!(vars(&p).get(\"subreddit\").map(String::as_str), Some(\"Rust\"));\n+    }\n+\n+    #[test]\n+    fn traverse_captures_post_id() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"aww\", \"comments\", \"abc123\"], &[]);\n+        assert_eq!(terminal(&p), Some(\"reddit_post\"));\n+        assert_eq!(vars(&p).get(\"post_id\").map(String::as_str), Some(\"abc123\"));\n+    }\n+\n+    #[test]\n+    fn traverse_absorbs_listing_suffix_stays_on_subreddit() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"rust\", \"hot\"], &[]);\n+        assert_eq!(terminal(&p), Some(\"reddit_subreddit\"));\n+        assert_eq!(canon(&p), \"https://reddit.com/r/rust\");\n+    }\n+\n+    #[test]\n+    fn traverse_absorbs_all_listing_suffixes() {\n+        for suffix in [\"hot\", \"top\", \"new\", \"rising\", \"controversial\"] {\n+            let p = test_parts(\"reddit.com\", &[\"r\", \"test\", suffix], &[]);\n+            assert_eq!(terminal(&p), Some(\"reddit_subreddit\"), \"suffix {suffix}\");\n+            assert_eq!(canon(&p), \"https://reddit.com/r/test\", \"suffix {suffix}\");\n+        }\n+    }\n+\n+    #[test]\n+    fn traverse_absorbs_post_title_slug() {\n+        let p = test_parts(\n+            \"reddit.com\",\n+            &[\"r\", \"rust\", \"comments\", \"aaa\", \"my_great_post_title\"],\n+            &[],\n+        );\n+        assert_eq!(terminal(&p), Some(\"reddit_post\"));\n+        assert_eq!(canon(&p), \"https://reddit.com/r/rust/comments/aaa\");\n+    }\n+\n+    #[test]\n+    fn traverse_unknown_segment_falls_back_to_generic() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"rust\", \"wiki\", \"faq\"], &[]);\n+        assert_eq!(terminal(&p), None);\n+        assert_eq!(canon(&p), \"https://reddit.com/r/rust/wiki/faq\");\n+    }\n+\n+    #[test]\n+    fn traverse_youtube_watch_requires_v_in_query() {\n+        let p = test_parts(\"youtube.com\", &[\"watch\"], &[(\"v\", \"xyz\")]);\n+        assert_eq!(terminal(&p), Some(\"youtube_watch\"));\n+    }\n+\n+    #[test]\n+    fn traverse_youtu_be_captures_vid_id() {\n+        let p = test_parts(\"youtu.be\", &[\"dQw4w9WgXcQ\"], &[]);\n+        assert_eq!(terminal(&p), Some(\"youtu_be_video\"));\n+        assert_eq!(vars(&p).get(\"vid_id\").map(String::as_str), Some(\"dQw4w9WgXcQ\"));\n+    }\n+\n+    #[test]\n+    fn traverse_shorts_sets_video_id_var() {\n+        let p = test_parts(\"youtube.com\", &[\"shorts\", \"abc99\"], &[]);\n+        assert_eq!(terminal(&p), Some(\"youtube_watch\"));\n+        assert_eq!(vars(&p).get(\"video_id\").map(String::as_str), Some(\"abc99\"));\n+    }\n+\n+    #[test]\n+    fn reddit_domain_canonical() {\n+        let p = test_parts(\"reddit.com\", &[], &[]);\n+        assert_eq!(canon(&p), \"https://reddit.com\");\n+    }\n+\n+    #[test]\n+    fn reddit_r_hub_canonical() {\n+        let p = test_parts(\"reddit.com\", &[\"r\"], &[]);\n+        assert_eq!(terminal(&p), Some(\"reddit_r_hub\"));\n+        assert_eq!(canon(&p), \"https://reddit.com/r\");\n+    }\n+\n+    #[test]\n+    fn reddit_subreddit_lowercases_name() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"AmITheAsshole\"], &[]);\n+        assert_eq!(canon(&p), \"https://reddit.com/r/amitheasshole\");\n+    }\n+\n+    #[test]\n+    fn reddit_host_aliases_old_new_www() {\n+        for host in [\"old.reddit.com\", \"new.reddit.com\", \"www.reddit.com\"] {\n+            let p = test_parts(host, &[\"r\", \"rust\"], &[]);\n+            assert_eq!(canon(&p), \"https://reddit.com/r/rust\", \"host {host}\");\n+        }\n+    }\n+\n+    #[test]\n+    fn reddit_post_strips_slug_and_query() {\n+        let p = test_parts(\n+            \"old.reddit.com\",\n+            &[\"r\", \"Rust\", \"comments\", \"1abc\", \"title_slug_here\"],\n+            &[(\"sort\", \"new\")],\n+        );\n+        assert_eq!(canon(&p), \"https://reddit.com/r/rust/comments/1abc\");\n+    }\n+\n+    #[test]\n+    fn reddit_post_multiple_slugs_absorbed() {\n+        let p = test_parts(\n+            \"reddit.com\",\n+            &[\"r\", \"x\", \"comments\", \"id1\", \"slug1\", \"extra\"],\n+            &[],\n+        );\n+        assert_eq!(canon(&p), \"https://reddit.com/r/x/comments/id1\");\n+    }\n+\n+    #[test]\n+    fn reddit_listing_with_query_only() {\n+        let p = test_parts(\"www.reddit.com\", &[\"r\", \"programming\"], &[(\"sort\", \"top\")]);\n+        assert_eq!(canon(&p), \"https://reddit.com/r/programming\");\n+    }\n+\n+    #[test]\n+    fn reddit_subreddit_breadcrumbs_include_r_hub() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"movies\"], &[]);\n+        assert_eq!(\n+            crumbs(&p),\n+            vec![\n+                \"https://reddit.com\",\n+                \"https://reddit.com/r\",\n+                \"https://reddit.com/r/movies\"\n+            ]\n+        );\n+    }\n+\n+    #[test]\n+    fn reddit_post_breadcrumbs_skip_comments_node() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"aww\", \"comments\", \"1trnvdl\"], &[]);\n+        let c = crumbs(&p);\n+        assert!(!c.iter().any(|u| u.ends_with(\"/comments\")));\n+        assert_eq!(\n+            c.last().map(String::as_str),\n+            Some(\"https://reddit.com/r/aww/comments/1trnvdl\")\n+        );\n+        assert!(c.contains(&\"https://reddit.com/r/aww\".to_string()));\n+    }\n+\n+    #[test]\n+    fn reddit_post_parent_is_subreddit_not_comments() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"aww\", \"comments\", \"1trnvdl\"], &[]);\n+        let c = crumbs(&p);\n+        let parent = c.get(c.len() - 2).unwrap();\n+        assert_eq!(parent, \"https://reddit.com/r/aww\");\n+    }\n+\n+    #[test]\n+    fn reddit_domain_parent_is_none_in_breadcrumb_chain() {\n+        let p = test_parts(\"reddit.com\", &[], &[]);\n+        assert_eq!(crumbs(&p), vec![\"https://reddit.com\"]);\n+    }\n+\n+    #[test]\n+    fn youtube_watch_canonical_uses_v_only() {\n+        let p = test_parts(\"youtube.com\", &[\"watch\"], &[(\"v\", \"abc\"), (\"t\", \"99\")]);\n+        assert_eq!(canon(&p), \"https://youtube.com/watch?v=abc\");\n+    }\n+\n+    #[test]\n+    fn youtube_query_order_independent() {\n+        let a = test_parts(\"youtube.com\", &[\"watch\"], &[(\"v\", \"abc\"), (\"t\", \"4\")]);\n+        let b = test_parts(\"youtube.com\", &[\"watch\"], &[(\"t\", \"4\"), (\"v\", \"abc\")]);\n+        assert_eq!(canon(&a), canon(&b));\n+    }\n+\n+    #[test]\n+    fn youtube_host_aliases() {\n+        for host in [\"www.youtube.com\", \"m.youtube.com\"] {\n+            let p = test_parts(host, &[\"watch\"], &[(\"v\", \"x\")]);\n+            assert_eq!(canon(&p), \"https://youtube.com/watch?v=x\", \"host {host}\");\n+        }\n+    }\n+\n+    #[test]\n+    fn youtube_shorts_canonical_matches_watch() {\n+        let shorts = test_parts(\"youtube.com\", &[\"shorts\", \"vid123\"], &[]);\n+        let watch = test_parts(\"youtube.com\", &[\"watch\"], &[(\"v\", \"vid123\")]);\n+        assert_eq!(canon(&shorts), canon(&watch));\n+        assert_eq!(canon(&shorts), \"https://youtube.com/watch?v=vid123\");\n+    }\n+\n+    #[test]\n+    fn youtu_be_matches_youtube_watch() {\n+        let be = test_parts(\"youtu.be\", &[\"dQw4w9WgXcQ\"], &[]);\n+        let watch = test_parts(\"youtube.com\", &[\"watch\"], &[(\"v\", \"dQw4w9WgXcQ\")]);\n+        assert_eq!(canon(&be), canon(&watch));\n+    }\n+\n+    #[test]\n+    fn youtube_breadcrumbs_domain_then_watch() {\n+        let p = test_parts(\"youtube.com\", &[\"watch\"], &[(\"v\", \"abc\")]);\n+        assert_eq!(\n+            crumbs(&p),\n+            vec![\"https://youtube.com\", \"https://youtube.com/watch?v=abc\"]\n+        );\n+    }\n+\n+    #[test]\n+    fn youtu_be_breadcrumbs_include_youtube_domain() {\n+        let p = test_parts(\"youtu.be\", &[\"abc\"], &[]);\n+        let c = crumbs(&p);\n+        assert_eq!(c.first().map(String::as_str), Some(\"https://youtube.com\"));\n+        assert_eq!(\n+            c.last().map(String::as_str),\n+            Some(\"https://youtube.com/watch?v=abc\")\n+        );\n+    }\n+\n+    #[test]\n+    fn parsed_urls_match_hand_built_parts() {\n+        let raw = \"https://www.reddit.com/r/rust/comments/aaa/title/?utm=x\";\n+        let parsed = UrlParts::parse(raw).unwrap();\n+        let hand = test_parts(\n+            \"www.reddit.com\",\n+            &[\"r\", \"rust\", \"comments\", \"aaa\", \"title\"],\n+            &[(\"utm\", \"x\")],\n+        );\n+        assert_eq!(canon(&parsed), canon(&hand));\n+    }\n+\n+    #[test]\n+    fn equivalence_cluster_youtube_formats() {\n+        let urls = [\n+            \"https://youtu.be/abc123\",\n+            \"https://www.youtube.com/watch?v=abc123\",\n+            \"https://youtube.com/watch?v=abc123&t=1\",\n+            \"https://m.youtube.com/watch?t=1&v=abc123\",\n+        ];\n+        let canonical: Vec<_> = urls\n+            .iter()\n+            .map(|u| canon(&UrlParts::parse(u).unwrap()))\n+            .collect();\n+        assert!(canonical.iter().all(|c| *c == \"https://youtube.com/watch?v=abc123\"));\n+    }\n+\n+    #[test]\n+    fn equivalence_cluster_reddit_post_formats() {\n+        let urls = [\n+            \"https://old.reddit.com/r/Rust/comments/aaa/slug/\",\n+            \"reddit.com/r/rust/comments/aaa/other_slug\",\n+            \"https://reddit.com/r/RUST/comments/aaa\",\n+        ];\n+        let canonical: Vec<_> = urls\n+            .iter()\n+            .map(|u| canon(&UrlParts::parse(u).unwrap()))\n+            .collect();\n+        assert!(\n+            canonical\n+                .iter()\n+                .all(|c| *c == \"https://reddit.com/r/rust/comments/aaa\")\n+        );\n+    }\n+\n+    #[test]\n+    fn graph_nodes_all_have_valid_parent_links() {\n+        let g = build_graph();\n+        for (id, node) in &g.nodes {\n+            if let Some(parent) = node.parent {\n+                assert!(g.nodes.contains_key(parent), \"node {id} parent {parent}\");\n+            }\n+        }\n+    }\n+\n+    #[test]\n+    fn graph_terminal_canonical_always_succeeds_for_reddit_paths() {\n+        let cases: &[(&[&str], &str)] = &[\n+            (&[\"r\", \"rust\"], \"https://reddit.com/r/rust\"),\n+            (\n+                &[\"r\", \"rust\", \"comments\", \"x\"],\n+                \"https://reddit.com/r/rust/comments/x\",\n+            ),\n+        ];\n+        for (segs, want) in cases {\n+            let p = test_parts(\"reddit.com\", segs, &[]);\n+            assert_eq!(canon(&p), *want);\n+        }\n+    }\n+\n+    #[test]\n+    fn breadcrumb_parent_walk_matches_parent_url_semantics() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"aww\", \"comments\", \"id1\"], &[]);\n+        let c = crumbs(&p);\n+        assert_eq!(c.len(), 4);\n+        assert_eq!(\n+            c.get(c.len() - 2).map(String::as_str),\n+            Some(\"https://reddit.com/r/aww\")\n+        );\n+    }\n+\n+    #[test]\n+    fn youtube_watch_without_v_falls_back_to_generic() {\n+        let p = test_parts(\"youtube.com\", &[\"watch\"], &[]);\n+        assert_eq!(terminal(&p), Some(\"youtube_watch\"));\n+        assert_eq!(canon(&p), \"https://youtube.com/watch\");\n+    }\n+\n+    #[test]\n+    fn reddit_only_comments_path_stops_at_gate() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"rust\", \"comments\"], &[]);\n+        assert_eq!(terminal(&p), Some(\"reddit_comments_gate\"));\n+        assert_eq!(canon(&p), \"https://reddit.com/r/rust\");\n+    }\n+\n+    #[test]\n+    fn generic_deep_path_many_segments() {\n+        let segs: Vec<&str> = (0..10)\n+            .map(|i| match i {\n+                0 => \"a\",\n+                1 => \"b\",\n+                2 => \"c\",\n+                3 => \"d\",\n+                4 => \"e\",\n+                5 => \"f\",\n+                6 => \"g\",\n+                7 => \"h\",\n+                8 => \"i\",\n+                _ => \"j\",\n+            })\n+            .collect();\n+        let p = test_parts(\"site.com\", &segs, &[]);\n+        assert_eq!(crumbs(&p).len(), 11);\n+    }\n+\n+    #[test]\n+    fn traverse_literal_r_required_for_subreddit() {\n+        let p = test_parts(\"reddit.com\", &[\"rust\"], &[]);\n+        assert_eq!(terminal(&p), None);\n+    }\n+\n+    #[test]\n+    fn http_scheme_upgraded_via_generic_fallback_host() {\n+        let parsed = UrlParts::parse(\"http://example.com/page\").unwrap();\n+        assert_eq!(canon(&parsed), \"https://example.com/page\");\n+    }\n+\n+    #[test]\n+    fn each_graph_node_canonical_is_invokable() {\n+        let g = build_graph();\n+        let empty = Context::default();\n+        for (id, node) in &g.nodes {\n+            let _ = (node.canonical)(&empty);\n+            let _ = id;\n+        }\n+    }\n+\n+    #[test]\n+    fn reddit_double_listing_suffix_both_absorbed() {\n+        let p = test_parts(\"reddit.com\", &[\"r\", \"rust\", \"hot\", \"new\"], &[]);\n+        assert_eq!(terminal(&p), Some(\"reddit_subreddit\"));\n+        assert_eq!(canon(&p), \"https://reddit.com/r/rust\");\n+    }\n+\n+    #[test]\n+    fn youtu_be_empty_path_stays_at_entry() {\n+        let p = test_parts(\"youtu.be\", &[], &[]);\n+        assert_eq!(terminal(&p), Some(\"youtu_be_entry\"));\n+    }\n+}\ndiff --git a/server/src/url_rules/graph_builder.rs b/server/src/url_rules/graph_builder.rs\nnew file mode 100644\nindex 0000000000000000000000000000000000000000..243204ad5ca514fff459057956080cacb5bf38e2\n--- /dev/null\n+++ b/server/src/url_rules/graph_builder.rs\n@@ -0,0 +1,73 @@\n+//! Declarative construction of the URL graph with build-time link validation.\n+\n+use std::collections::HashMap;\n+\n+use super::graph::{CanonicalFn, Edge, EdgePattern, Graph, Node};\n+\n+pub struct GraphBuilder {\n+    nodes: HashMap<&'static str, Node>,\n+    current: Option<&'static str>,\n+}\n+\n+impl GraphBuilder {\n+    pub fn new() -> Self {\n+        Self {\n+            nodes: HashMap::new(),\n+            current: None,\n+        }\n+    }\n+\n+    pub fn node(mut self, id: &'static str) -> Self {\n+        self.nodes.entry(id).or_insert_with(Node::empty);\n+        self.current = Some(id);\n+        self\n+    }\n+\n+    pub fn canonical(mut self, f: CanonicalFn) -> Self {\n+        let id = self.current.expect(\"canonical() without node()\");\n+        self.nodes.get_mut(id).expect(\"node missing\").canonical = f;\n+        self\n+    }\n+\n+    pub fn parent(mut self, parent_id: &'static str) -> Self {\n+        let id = self.current.expect(\"parent() without node()\");\n+        self.nodes.get_mut(id).expect(\"node missing\").parent = Some(parent_id);\n+        self\n+    }\n+\n+    pub fn edge(mut self, pattern: EdgePattern, target: &'static str) -> Self {\n+        let id = self.current.expect(\"edge() without node()\");\n+        self.nodes\n+            .get_mut(id)\n+            .expect(\"node missing\")\n+            .edges\n+            .push(Edge { pattern, target });\n+        self\n+    }\n+\n+    pub fn build(self) -> Graph {\n+        for (id, node) in &self.nodes {\n+            if let Some(parent) = node.parent {\n+                assert!(\n+                    self.nodes.contains_key(parent),\n+                    \"node {id}: parent {parent} does not exist\"\n+                );\n+            }\n+            for edge in &node.edges {\n+                if !matches!(\n+                    edge.pattern,\n+                    EdgePattern::AbsorbAny | EdgePattern::AbsorbIf(_)\n+                ) {\n+                    assert!(\n+                        self.nodes.contains_key(edge.target),\n+                        \"node {id}: edge target {} does not exist\",\n+                        edge.target\n+                    );\n+                }\n+            }\n+        }\n+        Graph {\n+            nodes: self.nodes,\n+        }\n+    }\n+}\ndiff --git a/server/src/url_rules/mod.rs b/server/src/url_rules/mod.rs\nindex 9e1445346ce77a49dd6a7e7713bf9c57aef353cc..ba4ac662acc7bd4d50ee34613eb7eb6fccbfb17b 100644\n--- a/server/src/url_rules/mod.rs\n+++ b/server/src/url_rules/mod.rs\n@@ -1,6 +1,7 @@\n //! URL canonicalization and hierarchy via a semantic graph (DFA + generic fallback).\n \n mod graph;\n+mod graph_builder;\n mod parse;\n mod registry;\n \ndiff --git a/server/src/url_rules/parse.rs b/server/src/url_rules/parse.rs\nnew file mode 100644\nindex 0000000000000000000000000000000000000000..19d0c82feb718817168b8b445fcbfa39cf6aa6ba\n--- /dev/null\n+++ b/server/src/url_rules/parse.rs\n@@ -0,0 +1,169 @@\n+//! Parse raw strings into host, path segments, and query (order-independent).\n+\n+use std::collections::HashMap;\n+\n+use url::Url;\n+\n+#[derive(Debug, Clone)]\n+pub struct UrlParts {\n+    pub scheme: String,\n+    pub host: String,\n+    pub path_segments: Vec<String>,\n+    pub query: HashMap<String, String>,\n+}\n+\n+impl UrlParts {\n+    pub fn parse(raw: &str) -> Option<Self> {\n+        let trimmed = raw.trim();\n+        if trimmed.is_empty() {\n+            return None;\n+        }\n+\n+        let with_scheme = if trimmed.contains(\"://\") {\n+            trimmed.to_string()\n+        } else if trimmed.starts_with(\"r/\") || trimmed.starts_with(\"/r/\") {\n+            let rest = trimmed.trim_start_matches('/').trim_start_matches(\"r/\");\n+            format!(\"https://reddit.com/r/{rest}\")\n+        } else if trimmed.contains('.') && !trimmed.starts_with('/') {\n+            format!(\"https://{trimmed}\")\n+        } else {\n+            trimmed.to_string()\n+        };\n+\n+        let url = Url::parse(&with_scheme).ok()?;\n+        let host = url.host_str()?.to_string();\n+        let path_segments: Vec<String> = url\n+            .path_segments()\n+            .map(|segs| segs.filter(|s| !s.is_empty()).map(str::to_string).collect())\n+            .unwrap_or_default();\n+\n+        let mut query = HashMap::new();\n+        for (k, v) in url.query_pairs() {\n+            query.insert(k.into_owned(), v.into_owned());\n+        }\n+\n+        Some(Self {\n+            scheme: url.scheme().to_string(),\n+            path_segments,\n+            query,\n+            host,\n+        })\n+    }\n+\n+    /// Host normalized for graph entry matching (lowercase, aliases).\n+    pub fn match_host(&self) -> String {\n+        normalize_match_host(&self.host)\n+    }\n+}\n+\n+pub fn normalize_match_host(host: &str) -> String {\n+    let h = host\n+        .strip_prefix(\"www.\")\n+        .unwrap_or(host)\n+        .to_ascii_lowercase();\n+    match h.as_str() {\n+        \"old.reddit.com\" | \"new.reddit.com\" => \"reddit.com\".to_string(),\n+        \"m.youtube.com\" => \"youtube.com\".to_string(),\n+        _ => h,\n+    }\n+}\n+\n+pub fn strip_tracking_query(query: &mut HashMap<String, String>) {\n+    query.retain(|k, _| {\n+        let lower = k.to_ascii_lowercase();\n+        !(lower.starts_with(\"utm_\")\n+            || matches!(\n+                lower.as_str(),\n+                \"fbclid\" | \"gclid\" | \"ref\" | \"ref_src\" | \"ref_source\" | \"mc_cid\" | \"mc_eid\"\n+            ))\n+    });\n+}\n+\n+#[cfg(test)]\n+pub(crate) fn test_parts(host: &str, segs: &[&str], query: &[(&str, &str)]) -> UrlParts {\n+    UrlParts {\n+        scheme: \"https\".to_string(),\n+        host: host.to_string(),\n+        path_segments: segs.iter().map(|s| (*s).to_string()).collect(),\n+        query: query\n+            .iter()\n+            .map(|(k, v)| (k.to_string(), v.to_string()))\n+            .collect(),\n+    }\n+}\n+\n+#[cfg(test)]\n+mod tests {\n+    use super::*;\n+\n+    #[test]\n+    fn parse_full_url_splits_host_path_query() {\n+        let p = UrlParts::parse(\"https://www.youtube.com/watch?v=abc&t=4\").unwrap();\n+        assert_eq!(p.host, \"www.youtube.com\");\n+        assert_eq!(p.path_segments, vec![\"watch\"]);\n+        assert_eq!(p.query.get(\"v\").map(String::as_str), Some(\"abc\"));\n+        assert_eq!(p.query.get(\"t\").map(String::as_str), Some(\"4\"));\n+    }\n+\n+    #[test]\n+    fn parse_r_shortcut_expands_to_reddit() {\n+        let p = UrlParts::parse(\"r/rust\").unwrap();\n+        assert_eq!(p.match_host(), \"reddit.com\");\n+        assert_eq!(p.path_segments, vec![\"r\", \"rust\"]);\n+    }\n+\n+    #[test]\n+    fn parse_slash_r_shortcut() {\n+        let p = UrlParts::parse(\"/r/aww\").unwrap();\n+        assert_eq!(p.path_segments, vec![\"r\", \"aww\"]);\n+    }\n+\n+    #[test]\n+    fn parse_schemeless_host_path() {\n+        let p = UrlParts::parse(\"reddit.com/r/rust/comments/aaa/slug\").unwrap();\n+        assert_eq!(p.match_host(), \"reddit.com\");\n+        assert_eq!(\n+            p.path_segments,\n+            vec![\"r\", \"rust\", \"comments\", \"aaa\", \"slug\"]\n+        );\n+    }\n+\n+    #[test]\n+    fn parse_empty_returns_none() {\n+        assert!(UrlParts::parse(\"\").is_none());\n+        assert!(UrlParts::parse(\"   \").is_none());\n+    }\n+\n+    #[test]\n+    fn normalize_match_host_reddit_aliases() {\n+        assert_eq!(normalize_match_host(\"old.reddit.com\"), \"reddit.com\");\n+        assert_eq!(normalize_match_host(\"NEW.reddit.com\"), \"reddit.com\");\n+        assert_eq!(normalize_match_host(\"www.reddit.com\"), \"reddit.com\");\n+    }\n+\n+    #[test]\n+    fn normalize_match_host_youtube_aliases() {\n+        assert_eq!(normalize_match_host(\"m.youtube.com\"), \"youtube.com\");\n+        assert_eq!(normalize_match_host(\"www.youtube.com\"), \"youtube.com\");\n+    }\n+\n+    #[test]\n+    fn strip_tracking_query_removes_known_params() {\n+        let mut q = HashMap::from([\n+            (\"v\".into(), \"1\".into()),\n+            (\"utm_source\".into(), \"x\".into()),\n+            (\"fbclid\".into(), \"y\".into()),\n+            (\"ref\".into(), \"z\".into()),\n+        ]);\n+        strip_tracking_query(&mut q);\n+        assert_eq!(q.len(), 1);\n+        assert_eq!(q.get(\"v\").map(String::as_str), Some(\"1\"));\n+    }\n+\n+    #[test]\n+    fn strip_tracking_query_utm_prefix() {\n+        let mut q = HashMap::from([(\"utm_campaign\".into(), \"email\".into())]);\n+        strip_tracking_query(&mut q);\n+        assert!(q.is_empty());\n+    }\n+}\ndiff --git a/server/src/url_rules/registry_tests.rs b/server/src/url_rules/registry_tests.rs\nnew file mode 100644\nindex 0000000000000000000000000000000000000000..7b76b550f808f590e011469fdae02adf603b43d2\n--- /dev/null\n+++ b/server/src/url_rules/registry_tests.rs\n@@ -0,0 +1,195 @@\n+//! End-to-end tests for the public registry API (`canonicalize_raw`, breadcrumbs, parent).\n+\n+use super::registry::{\n+    canonicalize_raw, looks_like_url, navigable_breadcrumbs, parent_url, resolve_id,\n+};\n+\n+fn canon(raw: &str) -> String {\n+    canonicalize_raw(raw).unwrap().canonical\n+}\n+\n+#[test]\n+fn looks_like_url_positive_cases() {\n+    for raw in [\n+        \"https://reddit.com/r/rust\",\n+        \"r/rust\",\n+        \"/r/aww\",\n+        \"reddit.com/r/x\",\n+        \"www.example.com/path\",\n+        \"youtu.be/abc\",\n+    ] {\n+        assert!(looks_like_url(raw), \"{raw}\");\n+    }\n+}\n+\n+#[test]\n+fn looks_like_url_negative_cases() {\n+    for raw in [\"alpha\", \"beta\", \"\", \"hello world\", \"no-dots\"] {\n+        assert!(!looks_like_url(raw), \"{raw}\");\n+    }\n+}\n+\n+#[test]\n+fn resolve_id_matches_canonicalize_raw() {\n+    let raw = \"https://youtu.be/xyz\";\n+    assert_eq!(\n+        resolve_id(raw).as_deref(),\n+        Some(canon(raw).as_str())\n+    );\n+}\n+\n+#[test]\n+fn canonicalize_empty_returns_none() {\n+    assert!(canonicalize_raw(\"\").is_none());\n+}\n+\n+#[test]\n+fn alias_when_slug_stripped() {\n+    let r = canonicalize_raw(\n+        \"https://reddit.com/r/rust/comments/aaa/very_long_title_slug\",\n+    )\n+    .unwrap();\n+    assert_eq!(r.canonical, \"https://reddit.com/r/rust/comments/aaa\");\n+    assert!(r.alias_of.is_some());\n+}\n+\n+#[test]\n+fn alias_none_when_already_canonical() {\n+    let raw = \"https://reddit.com/r/rust\";\n+    let r = canonicalize_raw(raw).unwrap();\n+    assert_eq!(r.canonical, raw);\n+    assert!(r.alias_of.is_none());\n+}\n+\n+#[test]\n+fn parent_url_subreddit_under_r_hub() {\n+    assert_eq!(\n+        parent_url(\"https://reddit.com/r/movies\").as_deref(),\n+        Some(\"https://reddit.com/r\")\n+    );\n+}\n+\n+#[test]\n+fn parent_url_domain_has_none() {\n+    assert_eq!(parent_url(\"https://reddit.com\").as_deref(), None);\n+}\n+\n+#[test]\n+fn parent_url_generic_site() {\n+    assert_eq!(\n+        parent_url(\"https://example.com/a/b\").as_deref(),\n+        Some(\"https://example.com/a\")\n+    );\n+}\n+\n+#[test]\n+fn breadcrumbs_from_canonical_string_roundtrip() {\n+    let id = \"https://reddit.com/r/golang/comments/abc123\";\n+    let crumbs = navigable_breadcrumbs(id);\n+    assert_eq!(crumbs.last().map(String::as_str), Some(id));\n+}\n+\n+// --- Table: Reddit raw URLs → canonical ---\n+\n+#[test]\n+fn reddit_canonical_matrix() {\n+    let cases: &[(&str, &str)] = &[\n+        (\"r/rust\", \"https://reddit.com/r/rust\"),\n+        (\"/r/aww\", \"https://reddit.com/r/aww\"),\n+        (\"https://reddit.com/r/rust\", \"https://reddit.com/r/rust\"),\n+        (\n+            \"https://www.reddit.com/r/programming/new\",\n+            \"https://reddit.com/r/programming\",\n+        ),\n+        (\n+            \"https://old.reddit.com/r/test/comments/xyz/slug/\",\n+            \"https://reddit.com/r/test/comments/xyz\",\n+        ),\n+        (\n+            \"reddit.com/r/Movies/comments/abc/Title_Case_Slug\",\n+            \"https://reddit.com/r/movies/comments/abc\",\n+        ),\n+    ];\n+    for (raw, want) in cases {\n+        assert_eq!(canon(raw), *want, \"raw={raw}\");\n+    }\n+}\n+\n+// --- Table: YouTube raw URLs → canonical ---\n+\n+#[test]\n+fn youtube_canonical_matrix() {\n+    let cases: &[(&str, &str)] = &[\n+        (\n+            \"https://youtube.com/watch?v=abc\",\n+            \"https://youtube.com/watch?v=abc\",\n+        ),\n+        (\n+            \"https://www.youtube.com/watch?v=abc&t=1&feature=share\",\n+            \"https://youtube.com/watch?v=abc\",\n+        ),\n+        (\"https://youtu.be/abc\", \"https://youtube.com/watch?v=abc\"),\n+        (\n+            \"https://youtube.com/shorts/abc\",\n+            \"https://youtube.com/watch?v=abc\",\n+        ),\n+    ];\n+    for (raw, want) in cases {\n+        assert_eq!(canon(raw), *want, \"raw={raw}\");\n+    }\n+}\n+\n+// --- Table: generic sites ---\n+\n+#[test]\n+fn generic_canonical_matrix() {\n+    let cases: &[(&str, &str)] = &[\n+        (\n+            \"https://news.ycombinator.com/item?id=38472\",\n+            \"https://news.ycombinator.com/item?id=38472\",\n+        ),\n+        (\n+            \"https://www.github.com/rust-lang/rust/issues/1?utm_source=x\",\n+            \"https://github.com/rust-lang/rust/issues/1\",\n+        ),\n+        (\"https://example.com\", \"https://example.com\"),\n+    ];\n+    for (raw, want) in cases {\n+        assert_eq!(canon(raw), *want, \"raw={raw}\");\n+    }\n+}\n+\n+// --- Phantom /comments/ regression (sorter2-specific) ---\n+\n+#[test]\n+fn phantom_comments_not_in_breadcrumbs_for_post() {\n+    let crumbs = navigable_breadcrumbs(\"https://reddit.com/r/rust/comments/aaa\");\n+    assert!(!crumbs.iter().any(|c| c.ends_with(\"/comments\")));\n+}\n+\n+#[test]\n+fn phantom_comments_not_sibling_of_subreddit_in_breadcrumb_chain() {\n+    let crumbs = navigable_breadcrumbs(\"https://reddit.com/r/rust/comments/aaa\");\n+    let subs: Vec<_> = crumbs\n+        .iter()\n+        .filter(|c| c.contains(\"/r/rust\") && !c.contains(\"/comments/\"))\n+        .collect();\n+    assert_eq!(subs, vec![\"https://reddit.com/r/rust\"]);\n+}\n+\n+// --- Distinct items must stay distinct ---\n+\n+#[test]\n+fn different_posts_different_canonical() {\n+    let a = canon(\"https://reddit.com/r/rust/comments/aaa\");\n+    let b = canon(\"https://reddit.com/r/rust/comments/bbb\");\n+    assert_ne!(a, b);\n+}\n+\n+#[test]\n+fn different_subreddits_different_canonical() {\n+    assert_ne!(\n+        canon(\"https://reddit.com/r/rust\"),\n+        canon(\"https://reddit.com/r/golang\")\n+    );\n+}\n","role":"user"}],"model":"openai/gpt-chat-latest"}