You are a constitutional council ranking individual git commits for ownership allocation.

Compare these two commits. Decide which contributed more lasting value to the project.

Judge substance, not spectacle:
- Prefer correct, lasting design and real bugfixes over churn, formatting, renames, or generated noise.
- Prefer clarity and necessity over sheer line count. A small precise change can beat a large diffuse one.
- Do not favor a side merely because its patch is longer or noisier.
- Weight what the change does for the project, not the contributor's name.

Return ONLY a JSON object: {"winner": "A" or "B", "ratio": "N:M", "explanation": "..."}
The explanation must cite concrete differences in the patches (1-3 sentences).

Side A — contributor: tommy-mor
Side A — commit message:
[8d8230d1] reddit

Side A — unified diff (full patch):
diff --git a/.gitignore b/.gitignore
index 4c7073f9fac0c30fd2050d79a60ef447af58ebeb..ada462e900d24a3a6d08165d158c80f79c35a5a5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@
 data/
 repomix-output.xml
 dev-data/
+.env
diff --git a/server/Cargo.toml b/server/Cargo.toml
index 7906a8547d56b8e6a48ef59c37aa82a8510fdee9..4677fedcb45292eebebe7e9cf6ce2f5738f18ddf 100644
--- a/server/Cargo.toml
+++ b/server/Cargo.toml
@@ -16,6 +16,7 @@ tower = "0.5"
 tower-http = { version = "0.5", features = ["trace"] }
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+reqwest = { version = "0.12", features = ["json"] }
 
 [dev-dependencies]
 reqwest = { version = "0.12", features = ["json"] }
diff --git a/server/src/html/mod.rs b/server/src/html/mod.rs
index 2864407ed6e8ec284a1dc663acf1805534566b62..df6505021d9f446c2b453e20e3eb3cf696a111f9 100644
--- a/server/src/html/mod.rs
+++ b/server/src/html/mod.rs
@@ -272,5 +272,16 @@ pub async fn home(State(state): State<AppState>, uri: Uri) -> impl IntoResponse
 
 pub async fn browse(State(state): State<AppState>, uri: Uri) -> impl IntoResponse {
     let item = ItemId::from_browse_uri(uri.path()).unwrap_or(ItemId::root());
+    if item.as_str().starts_with("reddit.com") {
+        let needs_fetch = {
+            let tree = state.tree.read().await;
+            tree.get(&item)
+                .map(|n| n.data.is_none())
+                .unwrap_or(true)
+        };
+        if needs_fetch {
+            state.reddit.request_fetch(item.clone());
+        }
+    }
     item_page(state, uri, item).await
 }
diff --git a/server/src/reddit.rs b/server/src/reddit.rs
index d203dca09245daf869b3aa942898447700ae69fb..90053ad03b1d7c8e94f325dd4ee64c2b4f7da900 100644
--- a/server/src/reddit.rs
+++ b/server/src/reddit.rs
@@ -1,4 +1,12 @@
-//! Reddit API import (async, decoupled from UI request path).
+//! Reddit API import via a single background worker (rate limits, dedup, backoff).
+
+use std::collections::{HashMap, HashSet};
+use std::sync::Arc;
+use std::time::{Duration, Instant};
+
+use reqwest::{header, Client, StatusCode};
+use serde::Deserialize;
+use tokio::sync::{mpsc, RwLock};
 
 use crate::{
     path_types::ItemId,
@@ -10,12 +18,401 @@ pub fn ensure_partial_tree(tree: &mut GlobalTree, id: &ItemId) {
     tree.ensure_path(id);
 }
 
-/// Placeholder for Reddit JSON import. Returns entity data when implemented.
-pub async fn fetch_reddit_entity(_id: &ItemId) -> Option<EntityData> {
-    None
+pub struct RedditCommand {
+    pub id: ItemId,
+}
+
+#[derive(Clone)]
+pub struct RedditBroker {
+    tx: mpsc::Sender<RedditCommand>,
+}
+
+#[derive(Clone)]
+struct RedditCredentials {
+    client_id: String,
+    client_secret: String,
+}
+
+struct OAuthToken {
+    access_token: String,
+    expires_at: Instant,
+}
+
+impl RedditBroker {
+    pub fn spawn(tree: Arc<RwLock<GlobalTree>>, user_agent: &str) -> Self {
+        let (tx, rx) = mpsc::channel(100);
+
+        let mut headers = header::HeaderMap::new();
+        headers.insert(
+            header::USER_AGENT,
+            header::HeaderValue::from_str(user_agent).expect("valid user agent"),
+        );
+
+        let client = Client::builder()
+            .default_headers(headers)
+            .timeout(Duration::from_secs(15))
+            .build()
+            .expect("reqwest client");
+
+        let creds = RedditCredentials::from_env();
+        tokio::spawn(reddit_worker(rx, tree, client, creds));
+
+        Self { tx }
+    }
+
+    /// Fire-and-forget: queue a fetch; worker updates the tree when done.
+    pub fn request_fetch(&self, id: ItemId) {
+        let _ = self.tx.try_send(RedditCommand { id });
+    }
+}
+
+impl RedditCredentials {
+    fn from_env() -> Option<Self> {
+        let client_id = std::env::var("REDDIT_CLIENT_ID").ok()?;
+        let client_secret = std::env::var("REDDIT_CLIENT_SECRET").ok()?;
+        if client_id.is_empty() || client_secret.is_empty() {
+            return None;
+        }
+        Some(Self {
+            client_id,
+            client_secret,
+        })
+    }
+}
+
+pub fn default_user_agent() -> String {
+    std::env::var("REDDIT_USER_AGENT").unwrap_or_else(|_| {
+        "web:sorter2.social:v0.0.1 (by /u/sorter2)".to_string()
+    })
 }
 
-/// Apply fetched entity data to a node (called from async worker).
-pub fn apply_entity(tree: &mut GlobalTree, id: &ItemId, data: EntityData) {
-    tree.set_entity_data(id, data);
+async fn reddit_worker(
+    mut rx: mpsc::Receiver<RedditCommand>,
+    tree: Arc<RwLock<GlobalTree>>,
+    client: Client,
+    creds: Option<RedditCredentials>,
+) {
+    let mut in_flight = HashSet::new();
+    let mut recently_fetched: HashMap<ItemId, Instant> = HashMap::new();
+    let mut current_delay = Duration::from_secs(1);
+    let mut oauth: Option<OAuthToken> = None;
+    let cache_ttl = Duration::from_secs(300);
+
+    while let Some(cmd) = rx.recv().await {
+        let now = Instant::now();
+        recently_fetched.retain(|_, t| now.duration_since(*t) < cache_ttl);
+
+        if in_flight.contains(&cmd.id) || recently_fetched.contains_key(&cmd.id) {
+            continue;
+        }
+
+        in_flight.insert(cmd.id.clone());
+        let fetch_id = cmd.id.clone();
+
+        tokio::time::sleep(current_delay).await;
+
+        if let Some(c) = &creds {
+            oauth = ensure_oauth_token(&client, c, oauth.take()).await;
+        }
+
+        let token = oauth.as_ref().map(|t| t.access_token.as_str());
+        let use_oauth = token.is_some();
+
+        match do_fetch(&client, &fetch_id, use_oauth, token).await {
+            Ok(FetchOutcome::Entity(data)) => {
+                let mut w = tree.write().await;
+                w.set_entity_data(&fetch_id, data);
+                recently_fetched.insert(fetch_id.clone(), Instant::now());
+                current_delay = Duration::from_millis(600);
+            }
+            Ok(FetchOutcome::NotFound) => {
+                recently_fetched.insert(fetch_id.clone(), Instant::now());
+            }
+            Ok(FetchOutcome::RateLimited { reset_secs }) => {
+                let wait = Duration::from_secs(reset_secs.max(1));
+                tracing::warn!(
+                    "Reddit rate limit for {}; sleeping {}s",
+                    fetch_id,
+                    wait.as_secs()
+                );
+                tokio::time::sleep(wait).await;
+                current_delay = (current_delay * 2).min(Duration::from_secs(60));
+            }
+            Err(e) => {
+                tracing::warn!("Reddit fetch failed for {}: {}", fetch_id, e);
+                current_delay = (current_delay * 2).min(Duration::from_secs(60));
+            }
+        }
+
+        in_flight.remove(&fetch_id);
+    }
+}
+
+enum FetchOutcome {
+    Entity(EntityData),
+    NotFound,
+    RateLimited { reset_secs: u64 },
+}
+
+async fn ensure_oauth_token(
+    client: &Client,
+    creds: &RedditCredentials,
+    existing: Option<OAuthToken>,
+) -> Option<OAuthToken> {
+    if let Some(t) = existing {
+        if Instant::now() < t.expires_at - Duration::from_secs(60) {
+            return Some(t);
+        }
+    }
+
+    let resp = client
+        .post("https://www.reddit.com/api/v1/access_token")
+        .basic_auth(&creds.client_id, Some(&creds.client_secret))
+        .form(&[("grant_type", "client_credentials")])
+        .send()
+        .await;
+
+    let resp = match resp {
+        Ok(r) => r,
+        Err(e) => {
+            tracing::warn!("Reddit OAuth token request failed: {e}");
+            return None;
+        }
+    };
+
+    if !resp.status().is_success() {
+        tracing::warn!("Reddit OAuth token HTTP {}", resp.status());
+        return None;
+    }
+
+    #[derive(Deserialize)]
+    struct TokenResponse {
+        access_token: String,
+        expires_in: u64,
+    }
+
+    let body: TokenResponse = match resp.json().await {
+        Ok(b) => b,
+        Err(e) => {
+            tracing::warn!("Reddit OAuth token parse failed: {e}");
+            return None;
+        }
+    };
+
+    Some(OAuthToken {
+        access_token: body.access_token,
+        expires_at: Instant::now() + Duration::from_secs(body.expires_in),
+    })
+}
+
+async fn do_fetch(
+    client: &Client,
+    id: &ItemId,
+    use_oauth: bool,
+    bearer: Option<&str>,
+) -> Result<FetchOutcome, String> {
+    let url = map_item_to_reddit_api(id, use_oauth);
+    if url.is_empty() {
+        return Ok(FetchOutcome::NotFound);
+    }
+
+    let mut req = client.get(&url);
+    if let Some(token) = bearer {
+        req = req.bearer_auth(token);
+    }
+
+    let resp = req.send().await.map_err(|e| e.to_string())?;
+
+    if resp.status() == StatusCode::TOO_MANY_REQUESTS {
+        let reset = rate_limit_reset_secs(&resp);
+        return Ok(FetchOutcome::RateLimited { reset_secs: reset });
+    }
+
+    if resp.status() == StatusCode::SERVICE_UNAVAILABLE {
+        return Err("Reddit unavailable (503)".to_string());
+    }
+
+    if !resp.status().is_success() {
+        return Ok(FetchOutcome::NotFound);
+    }
+
+    if rate_limit_remaining(&resp) == Some(0) {
+        let reset = rate_limit_reset_secs(&resp);
+        return Ok(FetchOutcome::RateLimited { reset_secs: reset });
+    }
+
+    let bytes = resp.bytes().await.map_err(|e| e.to_string())?;
+    Ok(parse_reddit_json(id, &bytes)
+        .map(FetchOutcome::Entity)
+        .unwrap_or(FetchOutcome::NotFound))
+}
+
+fn rate_limit_remaining(resp: &reqwest::Response) -> Option<u64> {
+    resp.headers()
+        .get("x-ratelimit-remaining")
+        .and_then(|v| v.to_str().ok())
+        .and_then(|s| s.parse::<f64>().ok())
+        .map(|f| f.floor() as u64)
+}
+
+fn rate_limit_reset_secs(resp: &reqwest::Response) -> u64 {
+    resp.headers()
+        .get("x-ratelimit-reset")
+        .and_then(|v| v.to_str().ok())
+        .and_then(|s| s.parse::<f64>().ok())
+        .map(|f| f.ceil() as u64)
+        .unwrap_or(5)
+}
+
+/// Map canonical item id to Reddit JSON API URL.
+pub fn map_item_to_reddit_api(id: &ItemId, oauth: bool) -> String {
+    let path = id.as_str();
+    if !path.starts_with("reddit.com/") && path != "reddit.com" {
+        return String::new();
+    }
+
+    let base = if oauth {
+        "https://oauth.reddit.com"
+    } else {
+        "https://www.reddit.com"
+    };
+
+    let segments: Vec<&str> = path.split('/').collect();
+
+    if let Some(i) = segments.iter().position(|&p| p == "comments") {
+        if segments.len() > i + 1 {
+            let api_path = segments[1..=i + 1].join("/");
+            return format!("{base}/{api_path}.json?raw_json=1");
+        }
+    }
+
+    if segments.len() == 3 && segments[1] == "r" {
+        return format!("{base}/r/{}/about.json?raw_json=1", segments[2]);
+    }
+
+    String::new()
+}
+
+fn parse_reddit_json(id: &ItemId, bytes: &[u8]) -> Option<EntityData> {
+    let v: serde_json::Value = serde_json::from_slice(bytes).ok()?;
+    let segments: Vec<&str> = id.as_str().split('/').collect();
+
+    if segments.iter().any(|&p| p == "comments") {
+        parse_post_listing(&v)
+    } else {
+        parse_subreddit_about(&v)
+    }
+}
+
+fn parse_subreddit_about(v: &serde_json::Value) -> Option<EntityData> {
+    let data = v.get("data")?;
+    let title = data
+        .get("title")
+        .or_else(|| data.get("display_name"))
+        .and_then(|t| t.as_str())?
+        .to_string();
+    let body_html = data
+        .get("public_description_html")
+        .or_else(|| data.get("public_description"))
+        .and_then(|t| t.as_str())
+        .map(|s| s.to_string());
+    let thumb_url = data
+        .get("icon_img")
+        .or_else(|| data.get("community_icon"))
+        .and_then(|t| t.as_str())
+        .filter(|s| !s.is_empty())
+        .map(|s| s.to_string());
+
+    Some(EntityData {
+        title,
+        author: None,
+        body_html,
+        thumb_url,
+    })
+}
+
+fn parse_post_listing(v: &serde_json::Value) -> Option<EntityData> {
+    let listing = v.as_array()?.first()?;
+    let child = listing
+        .pointer("/data/children/0/data")?;
+    let title = child.get("title")?.as_str()?.to_string();
+    let author = child
+        .get("author")
+        .and_then(|a| a.as_str())
+        .filter(|a| *a != "[deleted]")
+        .map(|s| s.to_string());
+    let body_html = child
+        .get("selftext_html")
+        .and_then(|t| t.as_str())
+        .filter(|s| !s.is_empty())
+        .map(|s| s.to_string());
+    let thumb_url = child
+        .get("thumbnail")
+        .and_then(|t| t.as_str())
+        .filter(|s| s.starts_with("http"))
+        .map(|s| s.to_string());
+
+    Some(EntityData {
+        title,
+        author,
+        body_html,
+        thumb_url,
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn map_subreddit_about_url() {
+        let id = ItemId::parse("reddit.com/r/rust").unwrap();
+        assert_eq!(
+            map_item_to_reddit_api(&id, false),
+            "https://www.reddit.com/r/rust/about.json?raw_json=1"
+        );
+        assert_eq!(
+            map_item_to_reddit_api(&id, true),
+            "https://oauth.reddit.com/r/rust/about.json?raw_json=1"
+        );
+    }
+
+    #[test]
+    fn map_post_url() {
+        let id =
+            ItemId::parse("reddit.com/r/amitheasshole/comments/1trnvdl").unwrap();
+        assert_eq!(
+            map_item_to_reddit_api(&id, false),
+            "https://www.reddit.com/r/amitheasshole/comments/1trnvdl.json?raw_json=1"
+        );
+    }
+
+    #[test]
+    fn map_non_reddit_empty() {
+        let id = ItemId::opaque("example.com/foo");
+        assert!(map_item_to_reddit_api(&id, false).is_empty());
+    }
+
+    #[test]
+    fn parse_subreddit_fixture() {
+        let json = r#"{"kind":"t5","data":{"title":"Rust","display_name":"rust","public_description":"systems"}}"#;
+        let entity = parse_reddit_json(
+            &ItemId::parse("reddit.com/r/rust").unwrap(),
+            json.as_bytes(),
+        )
+        .unwrap();
+        assert_eq!(entity.title, "Rust");
+    }
+
+    #[test]
+    fn parse_post_fixture() {
+        let json = r#"[{"kind":"Listing","data":{"children":[{"kind":"t3","data":{"title":"AITA","author":"op","selftext_html":"&lt;p&gt;hi&lt;/p&gt;","thumbnail":"https://b.thumbs.redditmedia.com/x.jpg"}}]}}]"#;
+        let entity = parse_reddit_json(
+            &ItemId::parse("reddit.com/r/x/comments/abc").unwrap(),
+            json.as_bytes(),
+        )
+        .unwrap();
+        assert_eq!(entity.title, "AITA");
+        assert_eq!(entity.author.as_deref(), Some("op"));
+    }
 }
diff --git a/server/src/state.rs b/server/src/state.rs
index cc1722f5a5bf4d415f2327ea585c488a15a75592..8c03aa60c15aee803a534439400b69935b1a3d84 100644
--- a/server/src/state.rs
+++ b/server/src/state.rs
@@ -5,9 +5,10 @@ use tokio::sync::RwLock;
 use crate::{
     event_log::EventLog,
     events::Event,
+    journal::JournalClient,
     path_types::ItemId,
+    reddit::{default_user_agent, RedditBroker},
     reducer::{GlobalTree, VoteData},
-    journal::JournalClient,
     views::ViewStore,
 };
 
@@ -73,6 +74,7 @@ pub struct AppState {
     pub views: ViewStore,
     pub tree: Arc<RwLock<GlobalTree>>,
     journal: JournalClient,
+    pub reddit: RedditBroker,
 }
 
 impl AppState {
@@ -112,6 +114,7 @@ impl AppState {
 
         let tree = Arc::new(RwLock::new(tree));
         let journal = JournalClient::spawn(tree.clone(), event_log.clone());
+        let reddit = RedditBroker::spawn(tree.clone(), &default_user_agent());
 
         Self {
             cfg: Arc::new(cfg),
@@ -119,6 +122,7 @@ impl AppState {
             views,
             tree,
             journal,
+            reddit,
         }
     }
 
@@ -127,8 +131,11 @@ impl AppState {
             id: id.as_str().to_string(),
         };
         self.event_log.append(&event).await.map_err(|e| e.to_string())?;
-        let mut w = self.tree.write().await;
-        w.ensure_path(id);
+        {
+            let mut w = self.tree.write().await;
+            w.ensure_path(id);
+        }
+        self.reddit.request_fetch(id.clone());
         Ok(())
     }
 
diff --git a/todo b/todo
new file mode 100644
index 0000000000000000000000000000000000000000..d196e8cb4cc80ccb95eeff01c73607d520e13212
--- /dev/null
+++ b/todo
@@ -0,0 +1,7 @@
+reddit import (only on explicit request)
+reddit rendering
+vote redering
+pair chosing
+nsfw gate
+
+logins (uuid user, two sides, oauths, and pseudonyms)


Side B — contributor: tommy-mor
Side B — commit message:
[07715165] nice

Side B — unified diff (full patch):
diff --git a/server/src/api/ui_html.rs b/server/src/api/ui_html.rs
index c3c62a76f424010d77a6090c84dd0b82098f573e..da2536112faea313352624cf2ce0ddd0ab3377c1 100644
--- a/server/src/api/ui_html.rs
+++ b/server/src/api/ui_html.rs
@@ -6,7 +6,7 @@ use axum::{
 use std::collections::HashMap;
 
 use crate::{
-    html::{demo_counter_panel, js_string_literal, ranking_panel, JsBuilder},
+    html::{js_string_literal, ranking_panel, JsBuilder},
     parser::parse_reddit_url,
     parser_render::parser_panel_morph,
     state::AppState,
@@ -35,13 +35,6 @@ pub async fn post_ui_html(
     };
 
     match action {
-        HtmlUiAction::BumpDemoCounter => {
-            let count = state.bump_demo_counter().await;
-            let panel = demo_counter_panel(count, state.event_log.path().to_string_lossy().as_ref());
-            JsBuilder::new()
-                .morph_selector("#demo-counter-panel", panel)
-                .into_response()
-        }
         HtmlUiAction::RecordVote {
             a,
             b,
@@ -54,8 +47,8 @@ pub async fn post_ui_html(
             {
                 return ui_js_warn(&e).into_response();
             }
-            let mut group = state.group.write().await;
-            let panel = ranking_panel(&mut group);
+            let group = state.group.read().await;
+            let panel = ranking_panel(&group);
             JsBuilder::new()
                 .morph_selector("#ranking-panel", panel)
                 .into_response()
@@ -87,20 +80,6 @@ mod tests {
         assert!(matches!(err, HtmlUiParseError::MissingRpc));
     }
 
-    #[test]
-    fn bump_action_deserializes() {
-        let template = serde_json::json!({ "action": "bump_demo_counter" });
-        let mut form = HashMap::new();
-        form.insert(
-            UI_RPC_FIELD.to_string(),
-            serde_json::to_string(&template).unwrap(),
-        );
-        assert_eq!(
-            parse_html_ui_from_form(&form).unwrap(),
-            HtmlUiAction::BumpDemoCounter
-        );
-    }
-
     #[test]
     fn record_vote_action_deserializes() {
         let template = serde_json::json!({
diff --git a/server/src/events.rs b/server/src/events.rs
index b969242534e184d4f0a689543a479670b08a18df..eff80aef0257f706d2341f666e63d6a3d921bf6e 100644
--- a/server/src/events.rs
+++ b/server/src/events.rs
@@ -5,8 +5,6 @@ use serde::{Deserialize, Serialize};
 pub enum Event {
     /// Page view recorded (path → counter in views.json).
     ViewRecorded { path: String, ts: i64 },
-    /// Demo counter bump from `POST /ui` (persisted in the single JSONL log).
-    DemoCounterBumped { ts: i64, value: u64 },
     /// Pairwise comparison vote (replayed into [`crate::reducer::GroupState`] on boot).
     VoteRecorded {
         ts: i64,
diff --git a/server/src/html/mod.rs b/server/src/html/mod.rs
index 5b1d0b5a887d89e7e80796aa7a6c8ed5baaf2782..d69ed962b5c8625bc83c933b1825f2cc1d0868e2 100644
--- a/server/src/html/mod.rs
+++ b/server/src/html/mod.rs
@@ -13,7 +13,7 @@ use crate::{
     form_template::template_json_compact,
     parser_action::ParserAction,
     parser_render::parser_panel,
-    ranking::ranked_items,
+    ranking::ranked_items_cached,
     reducer::GroupState,
     state::AppState,
     ui_action::UI_RPC_FIELD,
@@ -199,10 +199,8 @@ fn layout(title: &str, body: Markup, views: u64, theme: &str, theme_next: &str)
     }
 }
 
-pub fn ranking_panel(group: &mut GroupState) -> Markup {
-    const MAX_ITERS: usize = 10_000;
-    const TOL: f64 = 1e-8;
-    let items = ranked_items(group, MAX_ITERS, TOL);
+pub fn ranking_panel(group: &GroupState) -> Markup {
+    let items = ranked_items_cached(group);
     html! {
         section id="ranking-panel" class="demo-panel" {
             h2 { "Ranking" }
@@ -260,35 +258,6 @@ pub fn vote_panel() -> Markup {
 }
 
 
-pub fn demo_counter_panel(count: u64, event_log_path: &str) -> Markup {
-    let rpc = template_json_compact(&serde_json::json!({ "action": "bump_demo_counter" }))
-        .expect("rpc json");
-    html! {
-        section id="demo-counter-panel" class="demo-panel" {
-            h1 { "sorter2" }
-            p class="muted" {
-                "Pairwise ranking scaffold — votes persist to JSONL and replay on boot."
-            }
-            p class="demo-count" {
-                strong { "Counter: " }
-                span id="demo-count-value" { (count) }
-            }
-            p class="muted small" {
-                "Event log: " code { (event_log_path) }
-            }
-            form method="post" action="/ui" id="demo-bump-form" {
-                input type="hidden" name=(UI_RPC_FIELD) value=(rpc);
-                button type="submit" class="btn-primary" { "Bump (POST /ui → eval JS)" }
-            }
-            p class="muted small" {
-                "Uses hidden "
-                code { "__rpc__" }
-                " JSON + Idiomorph morph — no full page reload."
-            }
-        }
-    }
-}
-
 pub async fn home(
     State(state): State<AppState>,
     jar: CookieJar,
@@ -297,16 +266,15 @@ pub async fn home(
     let path = uri.path().to_string();
     state.views.increment(path.clone());
     let views = state.views.get_views(&path);
-    let count = *state.demo_counter.read().await;
     let theme = theme_from_jar(&jar);
     let theme_next = theme_next_from_uri(&uri);
-    let mut group = state.group.write().await;
+    let group = state.group.read().await;
     let empty_action = ParserAction::suggest(String::new(), None);
     let body = html! {
+        h1 { "sorter2" }
         (parser_panel("", &empty_action))
         (vote_panel())
-        (ranking_panel(&mut group))
-        (demo_counter_panel(count, state.event_log.path().to_string_lossy().as_ref()))
+        (ranking_panel(&group))
     };
     layout("sorter2", body, views, theme, &theme_next)
 }
diff --git a/server/src/lib.rs b/server/src/lib.rs
index 6716c5b282e7980a7a0f03d63ad8b25eda61cc55..fa423640d598f4ba97a5885d228e78d7b97f7a22 100644
--- a/server/src/lib.rs
+++ b/server/src/lib.rs
@@ -9,6 +9,7 @@ pub mod parser_render;
 pub mod path_types;
 pub mod ranking;
 pub mod reducer;
+pub mod settlement;
 pub mod state;
 pub mod ui_action;
 pub mod views;
diff --git a/server/src/ranking.rs b/server/src/ranking.rs
index 89d3280126a8d8f841721ce8cb63ff735d68752a..2d706762792ba9239bb3f1c2e4974a2fde908013 100644
--- a/server/src/ranking.rs
+++ b/server/src/ranking.rs
@@ -91,6 +91,11 @@ pub fn compute_group_ranking(group: &mut GroupState, max_iters: usize, tol: f64)
 
 pub fn ranked_items(group: &mut GroupState, max_iters: usize, tol: f64) -> Vec<RankedItem> {
     compute_group_ranking(group, max_iters, tol);
+    ranked_items_cached(group)
+}
+
+/// Read cached scores without recomputing (HTTP fast path).
+pub fn ranked_items_cached(group: &GroupState) -> Vec<RankedItem> {
     let mut items: Vec<RankedItem> = group
         .idx_to_item
         .iter()
@@ -105,7 +110,12 @@ pub fn ranked_items(group: &mut GroupState, max_iters: usize, tol: f64) -> Vec<R
     items
 }
 
-fn compute_scores_from_edges(n: usize, edges: impl Iterator<Item = ((usize, usize), f64)>, max_iters: usize, tol: f64) -> Vec<f64> {
+pub fn compute_scores_from_edges(
+    n: usize,
+    edges: impl Iterator<Item = ((usize, usize), f64)>,
+    max_iters: usize,
+    tol: f64,
+) -> Vec<f64> {
     if n == 0 {
         return vec![];
     }
diff --git a/server/src/settlement.rs b/server/src/settlement.rs
new file mode 100644
index 0000000000000000000000000000000000000000..1f722ceaea62cda22c28ab71551f259fbf049b81
--- /dev/null
+++ b/server/src/settlement.rs
@@ -0,0 +1,114 @@
+use std::sync::Arc;
+
+use tokio::sync::{mpsc, oneshot, RwLock};
+
+use crate::{
+    event_log::EventLog,
+    events::Event,
+    ranking::compute_scores_from_edges,
+    reducer::{GroupState, VoteData},
+};
+
+const MAX_ITERS: usize = 10_000;
+const TOL: f64 = 1e-8;
+
+pub struct SettlementCommand {
+    pub vote: VoteData,
+    pub event: Event,
+    pub reply: oneshot::Sender<Result<(), String>>,
+}
+
+#[derive(Clone)]
+pub struct SettlementClient {
+    tx: mpsc::Sender<SettlementCommand>,
+}
+
+impl SettlementClient {
+    pub fn spawn(group: Arc<RwLock<GroupState>>, event_log: Arc<EventLog>) -> Self {
+        let (tx, rx) = mpsc::channel(64);
+        tokio::spawn(settlement_worker(rx, group, event_log));
+        Self { tx }
+    }
+
+    pub async fn record_vote(&self, vote: VoteData, event: Event) -> Result<(), String> {
+        let (reply, rx) = oneshot::channel();
+        self.tx
+            .send(SettlementCommand {
+                vote,
+                event,
+                reply,
+            })
+            .await
+            .map_err(|_| "settlement worker stopped".to_string())?;
+        rx.await
+            .map_err(|_| "settlement worker stopped".to_string())?
+    }
+}
+
+async fn settlement_worker(
+    mut rx: mpsc::Receiver<SettlementCommand>,
+    group: Arc<RwLock<GroupState>>,
+    event_log: Arc<EventLog>,
+) {
+    while let Some(first) = rx.recv().await {
+        let mut batch = vec![first];
+        while let Ok(more) = rx.try_recv() {
+            batch.push(more);
+        }
+
+        let mut disk_err: Option<String> = None;
+        for cmd in &batch {
+            if let Err(e) = event_log.append(&cmd.event).await {
+                disk_err = Some(e.to_string());
+                break;
+            }
+        }
+
+        if let Some(err) = disk_err {
+            for cmd in batch {
+                let _ = cmd.reply.send(Err(err.clone()));
+            }
+            continue;
+        }
+
+        let (edges, n) = {
+            let mut w = group.write().await;
+            for cmd in &batch {
+                w.apply_vote(cmd.vote.clone());
+            }
+            (w.edges.clone(), w.idx_to_item.len())
+        };
+
+        let new_scores = compute_scores_from_edges(
+            n,
+            edges.iter().map(|(&k, &v)| (k, v)),
+            MAX_ITERS,
+            TOL,
+        );
+
+        {
+            let mut w = group.write().await;
+            w.cached_scores = new_scores;
+            w.dirty = false;
+        }
+
+        for cmd in batch {
+            let _ = cmd.reply.send(Ok(()));
+        }
+    }
+}
+
+/// Compute ranking cache from current in-memory edges (startup replay only).
+pub fn warm_ranking_cache(group: &mut GroupState) {
+    if !group.dirty {
+        return;
+    }
+    let n = group.idx_to_item.len();
+    group.cached_scores = compute_scores_from_edges(
+        n,
+        group.edges.iter().map(|(&k, &v)| (k, v)),
+        MAX_ITERS,
+        TOL,
+    );
+    group.dirty = false;
+}
diff --git a/server/src/state.rs b/server/src/state.rs
index 8ec9902e2ecc31cf8208f7ad6365891dc5537eed..1922541a4064c2de1df2d993a461cae783320e05 100644
--- a/server/src/state.rs
+++ b/server/src/state.rs
@@ -6,6 +6,7 @@ use crate::{
     event_log::EventLog,
     events::Event,
     reducer::{GroupState, VoteData},
+    settlement::{warm_ranking_cache, SettlementClient},
     views::ViewStore,
 };
 
@@ -38,8 +39,8 @@ pub struct AppState {
     pub cfg: Arc<AppConfig>,
     pub event_log: Arc<EventLog>,
     pub views: ViewStore,
-    pub demo_counter: Arc<RwLock<u64>>,
     pub group: Arc<RwLock<GroupState>>,
+    settlement: SettlementClient,
 }
 
 impl AppState {
@@ -48,14 +49,10 @@ impl AppState {
         let views_path = format!("{}/views.json", cfg.data_dir);
         let views = ViewStore::new(&views_path);
 
-        let mut demo_counter: u64 = 0;
         let mut group = GroupState::new();
         if let Ok((events, _)) = event_log.load_all().await {
             for ev in events {
                 match ev {
-                    Event::DemoCounterBumped { value, .. } => {
-                        demo_counter = demo_counter.max(value);
-                    }
                     Event::VoteRecorded {
                         ts,
                         a,
@@ -74,30 +71,20 @@ impl AppState {
             }
         }
 
+        warm_ranking_cache(&mut group);
+
+        let group = Arc::new(RwLock::new(group));
+        let settlement = SettlementClient::spawn(group.clone(), event_log.clone());
+
         Self {
             cfg: Arc::new(cfg),
             event_log,
             views,
-            demo_counter: Arc::new(RwLock::new(demo_counter)),
-            group: Arc::new(RwLock::new(group)),
+            group,
+            settlement,
         }
     }
 
-    pub async fn bump_demo_counter(&self) -> u64 {
-        let mut guard = self.demo_counter.write().await;
-        *guard += 1;
-        let value = *guard;
-        drop(guard);
-
-        let ts = crate::html::now_ms();
-        let _ = self
-            .event_log
-            .append(&Event::DemoCounterBumped { ts, value })
-            .await;
-
-        value
-    }
-
     pub async fn record_vote(
         &self,
         a: &str,
@@ -109,23 +96,14 @@ impl AppState {
         let vote = VoteData::from_recorded(ts, a, b, ratio_left, ratio_right)
             .ok_or_else(|| "invalid vote: need two distinct non-empty items".to_string())?;
 
-        {
-            let mut group = self.group.write().await;
-            group.apply_vote(vote.clone());
-        }
-
-        let _ = self
-            .event_log
-            .append(&Event::VoteRecorded {
-                ts,
-                a: vote.a.as_str().to_string(),
-                b: vote.b.as_str().to_string(),
-                ratio_left: vote.ratio_left,
-                ratio_right: vote.ratio_right,
-            })
-            .await
-            .map_err(|e| e.to_string())?;
+        let event = Event::VoteRecorded {
+            ts,
+            a: vote.a.as_str().to_string(),
+            b: vote.b.as_str().to_string(),
+            ratio_left: vote.ratio_left,
+            ratio_right: vote.ratio_right,
+        };
 
-        Ok(())
+        self.settlement.record_vote(vote, event).await
     }
 }
diff --git a/server/src/ui_action.rs b/server/src/ui_action.rs
index 1d488e1ad1d8fd81bd9d016d69255adfe9b22fc8..5d94c84113607b3bcd8d31d03ef5b8e1b87b67a7 100644
--- a/server/src/ui_action.rs
+++ b/server/src/ui_action.rs
@@ -12,8 +12,6 @@ pub const UI_RPC_FIELD: &str = "__rpc__";
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 #[serde(tag = "action", rename_all = "snake_case")]
 pub enum HtmlUiAction {
-    /// Demo: morph `#demo-counter-panel` after bumping the persisted counter.
-    BumpDemoCounter,
     /// Record a pairwise vote and morph `#ranking-panel`.
     RecordVote {
         a: String,
@@ -52,18 +50,6 @@ pub fn parse_html_ui_from_form(
 mod tests {
     use super::*;
 
-    #[test]
-    fn bump_demo_counter_round_trip() {
-        let template = serde_json::json!({ "action": "bump_demo_counter" });
-        let mut form = HashMap::new();
-        form.insert(
-            UI_RPC_FIELD.to_string(),
-            serde_json::to_string(&template).unwrap(),
-        );
-        let a = parse_html_ui_from_form(&form).unwrap();
-        assert_eq!(a, HtmlUiAction::BumpDemoCounter);
-    }
-
     #[test]
     fn record_vote_round_trip_with_form_holes() {
         let template = serde_json::json!({
diff --git a/server/tests/integration_health.rs b/server/tests/integration_health.rs
index 8a58bc14aac68c779e7ce4ffa57d27b3220e9953..1d816e008b9bf629967e3b3c786c41afefc284e3 100644
--- a/server/tests/integration_health.rs
+++ b/server/tests/integration_health.rs
@@ -38,7 +38,7 @@ async fn healthz_ok() {
 }
 
 #[tokio::test]
-async fn home_has_demo_panel() {
+async fn home_has_main_panels() {
     let (addr, _tmp) = start_test_server().await;
     let client = reqwest::Client::new();
     let html = client
diff --git a/server/tests/integration_ui.rs b/server/tests/integration_ui.rs
index bee79407dec120699a083f1a75adf9291e207fc7..7ede46d681fefbe25b1d98fc33520a185515eb1c 100644
--- a/server/tests/integration_ui.rs
+++ b/server/tests/integration_ui.rs
@@ -25,33 +25,6 @@ async fn start_test_server() -> (SocketAddr, TempDir) {
     (addr, tmp)
 }
 
-#[tokio::test]
-async fn post_ui_bump_returns_javascript_morph() {
-    let (addr, tmp) = start_test_server().await;
-    let rpc = serde_json::json!({ "action": "bump_demo_counter" }).to_string();
-    let mut form = HashMap::new();
-    form.insert(UI_RPC_FIELD.to_string(), rpc);
-
-    let client = reqwest::Client::new();
-    let body = client
-        .post(format!("http://{addr}/ui"))
-        .form(&form)
-        .send()
-        .await
-        .unwrap()
-        .text()
-        .await
-        .unwrap();
-
-    assert!(body.contains("Idiomorph.morph"));
-    assert!(body.contains("demo-counter-panel"));
-    assert!(body.contains("Counter:"));
-
-    let log_path = tmp.path().join("events.jsonl");
-    let log = std::fs::read_to_string(log_path).unwrap();
-    assert!(log.contains("demo_counter_bumped"));
-}
-
 #[tokio::test]
 async fn post_ui_record_vote_morphs_ranking_and_persists() {
     let (addr, tmp) = start_test_server().await;
@@ -90,8 +63,8 @@ async fn post_ui_record_vote_morphs_ranking_and_persists() {
         port: 0,
     };
     let state = create_app_state(cfg).await;
-    let mut group = state.group.write().await;
-    let ranked = sorter2_server::ranking::ranked_items(&mut group, 10_000, 1e-8);
+    let group = state.group.read().await;
+    let ranked = sorter2_server::ranking::ranked_items_cached(&group);
     assert_eq!(ranked.len(), 2);
     assert_eq!(ranked[0].item.as_str(), "alpha");
 }
diff --git a/test/smoke.clj b/test/smoke.clj
index b332324743b58baf3fe96d7477353749f137feae..11887c48282088e140d823a88ba616f6325835b3 100644
--- a/test/smoke.clj
+++ b/test/smoke.clj
@@ -26,7 +26,7 @@
             false))))))
 
 (deftest http-smoke-against-running-server
-  (testing "build, start, healthz, home contains RPC demo"
+  (testing "build, start, healthz, home contains main panels"
     (let [root (repo-root)
           data-dir (.getAbsolutePath (doto (io/file (System/getProperty "java.io.tmpdir")
                                                    (str "sorter2-smoke-" (System/currentTimeMillis)))