{"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[8d8230d1] reddit\n\nSide A — unified diff (full patch):\ndiff --git a/.gitignore b/.gitignore\nindex 4c7073f9fac0c30fd2050d79a60ef447af58ebeb..ada462e900d24a3a6d08165d158c80f79c35a5a5 100644\n--- a/.gitignore\n+++ b/.gitignore\n@@ -7,3 +7,4 @@\n data/\n repomix-output.xml\n dev-data/\n+.env\ndiff --git a/server/Cargo.toml b/server/Cargo.toml\nindex 7906a8547d56b8e6a48ef59c37aa82a8510fdee9..4677fedcb45292eebebe7e9cf6ce2f5738f18ddf 100644\n--- a/server/Cargo.toml\n+++ b/server/Cargo.toml\n@@ -16,6 +16,7 @@ tower = \"0.5\"\n tower-http = { version = \"0.5\", features = [\"trace\"] }\n tracing = \"0.1\"\n tracing-subscriber = { version = \"0.3\", features = [\"env-filter\"] }\n+reqwest = { version = \"0.12\", features = [\"json\"] }\n \n [dev-dependencies]\n reqwest = { version = \"0.12\", features = [\"json\"] }\ndiff --git a/server/src/html/mod.rs b/server/src/html/mod.rs\nindex 2864407ed6e8ec284a1dc663acf1805534566b62..df6505021d9f446c2b453e20e3eb3cf696a111f9 100644\n--- a/server/src/html/mod.rs\n+++ b/server/src/html/mod.rs\n@@ -272,5 +272,16 @@ pub async fn home(State(state): State<AppState>, uri: Uri) -> impl IntoResponse\n \n pub async fn browse(State(state): State<AppState>, uri: Uri) -> impl IntoResponse {\n     let item = ItemId::from_browse_uri(uri.path()).unwrap_or(ItemId::root());\n+    if item.as_str().starts_with(\"reddit.com\") {\n+        let needs_fetch = {\n+            let tree = state.tree.read().await;\n+            tree.get(&item)\n+                .map(|n| n.data.is_none())\n+                .unwrap_or(true)\n+        };\n+        if needs_fetch {\n+            state.reddit.request_fetch(item.clone());\n+        }\n+    }\n     item_page(state, uri, item).await\n }\ndiff --git a/server/src/reddit.rs b/server/src/reddit.rs\nindex d203dca09245daf869b3aa942898447700ae69fb..90053ad03b1d7c8e94f325dd4ee64c2b4f7da900 100644\n--- a/server/src/reddit.rs\n+++ b/server/src/reddit.rs\n@@ -1,4 +1,12 @@\n-//! Reddit API import (async, decoupled from UI request path).\n+//! Reddit API import via a single background worker (rate limits, dedup, backoff).\n+\n+use std::collections::{HashMap, HashSet};\n+use std::sync::Arc;\n+use std::time::{Duration, Instant};\n+\n+use reqwest::{header, Client, StatusCode};\n+use serde::Deserialize;\n+use tokio::sync::{mpsc, RwLock};\n \n use crate::{\n     path_types::ItemId,\n@@ -10,12 +18,401 @@ pub fn ensure_partial_tree(tree: &mut GlobalTree, id: &ItemId) {\n     tree.ensure_path(id);\n }\n \n-/// Placeholder for Reddit JSON import. Returns entity data when implemented.\n-pub async fn fetch_reddit_entity(_id: &ItemId) -> Option<EntityData> {\n-    None\n+pub struct RedditCommand {\n+    pub id: ItemId,\n+}\n+\n+#[derive(Clone)]\n+pub struct RedditBroker {\n+    tx: mpsc::Sender<RedditCommand>,\n+}\n+\n+#[derive(Clone)]\n+struct RedditCredentials {\n+    client_id: String,\n+    client_secret: String,\n+}\n+\n+struct OAuthToken {\n+    access_token: String,\n+    expires_at: Instant,\n+}\n+\n+impl RedditBroker {\n+    pub fn spawn(tree: Arc<RwLock<GlobalTree>>, user_agent: &str) -> Self {\n+        let (tx, rx) = mpsc::channel(100);\n+\n+        let mut headers = header::HeaderMap::new();\n+        headers.insert(\n+            header::USER_AGENT,\n+            header::HeaderValue::from_str(user_agent).expect(\"valid user agent\"),\n+        );\n+\n+        let client = Client::builder()\n+            .default_headers(headers)\n+            .timeout(Duration::from_secs(15))\n+            .build()\n+            .expect(\"reqwest client\");\n+\n+        let creds = RedditCredentials::from_env();\n+        tokio::spawn(reddit_worker(rx, tree, client, creds));\n+\n+        Self { tx }\n+    }\n+\n+    /// Fire-and-forget: queue a fetch; worker updates the tree when done.\n+    pub fn request_fetch(&self, id: ItemId) {\n+        let _ = self.tx.try_send(RedditCommand { id });\n+    }\n+}\n+\n+impl RedditCredentials {\n+    fn from_env() -> Option<Self> {\n+        let client_id = std::env::var(\"REDDIT_CLIENT_ID\").ok()?;\n+        let client_secret = std::env::var(\"REDDIT_CLIENT_SECRET\").ok()?;\n+        if client_id.is_empty() || client_secret.is_empty() {\n+            return None;\n+        }\n+        Some(Self {\n+            client_id,\n+            client_secret,\n+        })\n+    }\n+}\n+\n+pub fn default_user_agent() -> String {\n+    std::env::var(\"REDDIT_USER_AGENT\").unwrap_or_else(|_| {\n+        \"web:sorter2.social:v0.0.1 (by /u/sorter2)\".to_string()\n+    })\n }\n \n-/// Apply fetched entity data to a node (called from async worker).\n-pub fn apply_entity(tree: &mut GlobalTree, id: &ItemId, data: EntityData) {\n-    tree.set_entity_data(id, data);\n+async fn reddit_worker(\n+    mut rx: mpsc::Receiver<RedditCommand>,\n+    tree: Arc<RwLock<GlobalTree>>,\n+    client: Client,\n+    creds: Option<RedditCredentials>,\n+) {\n+    let mut in_flight = HashSet::new();\n+    let mut recently_fetched: HashMap<ItemId, Instant> = HashMap::new();\n+    let mut current_delay = Duration::from_secs(1);\n+    let mut oauth: Option<OAuthToken> = None;\n+    let cache_ttl = Duration::from_secs(300);\n+\n+    while let Some(cmd) = rx.recv().await {\n+        let now = Instant::now();\n+        recently_fetched.retain(|_, t| now.duration_since(*t) < cache_ttl);\n+\n+        if in_flight.contains(&cmd.id) || recently_fetched.contains_key(&cmd.id) {\n+            continue;\n+        }\n+\n+        in_flight.insert(cmd.id.clone());\n+        let fetch_id = cmd.id.clone();\n+\n+        tokio::time::sleep(current_delay).await;\n+\n+        if let Some(c) = &creds {\n+            oauth = ensure_oauth_token(&client, c, oauth.take()).await;\n+        }\n+\n+        let token = oauth.as_ref().map(|t| t.access_token.as_str());\n+        let use_oauth = token.is_some();\n+\n+        match do_fetch(&client, &fetch_id, use_oauth, token).await {\n+            Ok(FetchOutcome::Entity(data)) => {\n+                let mut w = tree.write().await;\n+                w.set_entity_data(&fetch_id, data);\n+                recently_fetched.insert(fetch_id.clone(), Instant::now());\n+                current_delay = Duration::from_millis(600);\n+            }\n+            Ok(FetchOutcome::NotFound) => {\n+                recently_fetched.insert(fetch_id.clone(), Instant::now());\n+            }\n+            Ok(FetchOutcome::RateLimited { reset_secs }) => {\n+                let wait = Duration::from_secs(reset_secs.max(1));\n+                tracing::warn!(\n+                    \"Reddit rate limit for {}; sleeping {}s\",\n+                    fetch_id,\n+                    wait.as_secs()\n+                );\n+                tokio::time::sleep(wait).await;\n+                current_delay = (current_delay * 2).min(Duration::from_secs(60));\n+            }\n+            Err(e) => {\n+                tracing::warn!(\"Reddit fetch failed for {}: {}\", fetch_id, e);\n+                current_delay = (current_delay * 2).min(Duration::from_secs(60));\n+            }\n+        }\n+\n+        in_flight.remove(&fetch_id);\n+    }\n+}\n+\n+enum FetchOutcome {\n+    Entity(EntityData),\n+    NotFound,\n+    RateLimited { reset_secs: u64 },\n+}\n+\n+async fn ensure_oauth_token(\n+    client: &Client,\n+    creds: &RedditCredentials,\n+    existing: Option<OAuthToken>,\n+) -> Option<OAuthToken> {\n+    if let Some(t) = existing {\n+        if Instant::now() < t.expires_at - Duration::from_secs(60) {\n+            return Some(t);\n+        }\n+    }\n+\n+    let resp = client\n+        .post(\"https://www.reddit.com/api/v1/access_token\")\n+        .basic_auth(&creds.client_id, Some(&creds.client_secret))\n+        .form(&[(\"grant_type\", \"client_credentials\")])\n+        .send()\n+        .await;\n+\n+    let resp = match resp {\n+        Ok(r) => r,\n+        Err(e) => {\n+            tracing::warn!(\"Reddit OAuth token request failed: {e}\");\n+            return None;\n+        }\n+    };\n+\n+    if !resp.status().is_success() {\n+        tracing::warn!(\"Reddit OAuth token HTTP {}\", resp.status());\n+        return None;\n+    }\n+\n+    #[derive(Deserialize)]\n+    struct TokenResponse {\n+        access_token: String,\n+        expires_in: u64,\n+    }\n+\n+    let body: TokenResponse = match resp.json().await {\n+        Ok(b) => b,\n+        Err(e) => {\n+            tracing::warn!(\"Reddit OAuth token parse failed: {e}\");\n+            return None;\n+        }\n+    };\n+\n+    Some(OAuthToken {\n+        access_token: body.access_token,\n+        expires_at: Instant::now() + Duration::from_secs(body.expires_in),\n+    })\n+}\n+\n+async fn do_fetch(\n+    client: &Client,\n+    id: &ItemId,\n+    use_oauth: bool,\n+    bearer: Option<&str>,\n+) -> Result<FetchOutcome, String> {\n+    let url = map_item_to_reddit_api(id, use_oauth);\n+    if url.is_empty() {\n+        return Ok(FetchOutcome::NotFound);\n+    }\n+\n+    let mut req = client.get(&url);\n+    if let Some(token) = bearer {\n+        req = req.bearer_auth(token);\n+    }\n+\n+    let resp = req.send().await.map_err(|e| e.to_string())?;\n+\n+    if resp.status() == StatusCode::TOO_MANY_REQUESTS {\n+        let reset = rate_limit_reset_secs(&resp);\n+        return Ok(FetchOutcome::RateLimited { reset_secs: reset });\n+    }\n+\n+    if resp.status() == StatusCode::SERVICE_UNAVAILABLE {\n+        return Err(\"Reddit unavailable (503)\".to_string());\n+    }\n+\n+    if !resp.status().is_success() {\n+        return Ok(FetchOutcome::NotFound);\n+    }\n+\n+    if rate_limit_remaining(&resp) == Some(0) {\n+        let reset = rate_limit_reset_secs(&resp);\n+        return Ok(FetchOutcome::RateLimited { reset_secs: reset });\n+    }\n+\n+    let bytes = resp.bytes().await.map_err(|e| e.to_string())?;\n+    Ok(parse_reddit_json(id, &bytes)\n+        .map(FetchOutcome::Entity)\n+        .unwrap_or(FetchOutcome::NotFound))\n+}\n+\n+fn rate_limit_remaining(resp: &reqwest::Response) -> Option<u64> {\n+    resp.headers()\n+        .get(\"x-ratelimit-remaining\")\n+        .and_then(|v| v.to_str().ok())\n+        .and_then(|s| s.parse::<f64>().ok())\n+        .map(|f| f.floor() as u64)\n+}\n+\n+fn rate_limit_reset_secs(resp: &reqwest::Response) -> u64 {\n+    resp.headers()\n+        .get(\"x-ratelimit-reset\")\n+        .and_then(|v| v.to_str().ok())\n+        .and_then(|s| s.parse::<f64>().ok())\n+        .map(|f| f.ceil() as u64)\n+        .unwrap_or(5)\n+}\n+\n+/// Map canonical item id to Reddit JSON API URL.\n+pub fn map_item_to_reddit_api(id: &ItemId, oauth: bool) -> String {\n+    let path = id.as_str();\n+    if !path.starts_with(\"reddit.com/\") && path != \"reddit.com\" {\n+        return String::new();\n+    }\n+\n+    let base = if oauth {\n+        \"https://oauth.reddit.com\"\n+    } else {\n+        \"https://www.reddit.com\"\n+    };\n+\n+    let segments: Vec<&str> = path.split('/').collect();\n+\n+    if let Some(i) = segments.iter().position(|&p| p == \"comments\") {\n+        if segments.len() > i + 1 {\n+            let api_path = segments[1..=i + 1].join(\"/\");\n+            return format!(\"{base}/{api_path}.json?raw_json=1\");\n+        }\n+    }\n+\n+    if segments.len() == 3 && segments[1] == \"r\" {\n+        return format!(\"{base}/r/{}/about.json?raw_json=1\", segments[2]);\n+    }\n+\n+    String::new()\n+}\n+\n+fn parse_reddit_json(id: &ItemId, bytes: &[u8]) -> Option<EntityData> {\n+    let v: serde_json::Value = serde_json::from_slice(bytes).ok()?;\n+    let segments: Vec<&str> = id.as_str().split('/').collect();\n+\n+    if segments.iter().any(|&p| p == \"comments\") {\n+        parse_post_listing(&v)\n+    } else {\n+        parse_subreddit_about(&v)\n+    }\n+}\n+\n+fn parse_subreddit_about(v: &serde_json::Value) -> Option<EntityData> {\n+    let data = v.get(\"data\")?;\n+    let title = data\n+        .get(\"title\")\n+        .or_else(|| data.get(\"display_name\"))\n+        .and_then(|t| t.as_str())?\n+        .to_string();\n+    let body_html = data\n+        .get(\"public_description_html\")\n+        .or_else(|| data.get(\"public_description\"))\n+        .and_then(|t| t.as_str())\n+        .map(|s| s.to_string());\n+    let thumb_url = data\n+        .get(\"icon_img\")\n+        .or_else(|| data.get(\"community_icon\"))\n+        .and_then(|t| t.as_str())\n+        .filter(|s| !s.is_empty())\n+        .map(|s| s.to_string());\n+\n+    Some(EntityData {\n+        title,\n+        author: None,\n+        body_html,\n+        thumb_url,\n+    })\n+}\n+\n+fn parse_post_listing(v: &serde_json::Value) -> Option<EntityData> {\n+    let listing = v.as_array()?.first()?;\n+    let child = listing\n+        .pointer(\"/data/children/0/data\")?;\n+    let title = child.get(\"title\")?.as_str()?.to_string();\n+    let author = child\n+        .get(\"author\")\n+        .and_then(|a| a.as_str())\n+        .filter(|a| *a != \"[deleted]\")\n+        .map(|s| s.to_string());\n+    let body_html = child\n+        .get(\"selftext_html\")\n+        .and_then(|t| t.as_str())\n+        .filter(|s| !s.is_empty())\n+        .map(|s| s.to_string());\n+    let thumb_url = child\n+        .get(\"thumbnail\")\n+        .and_then(|t| t.as_str())\n+        .filter(|s| s.starts_with(\"http\"))\n+        .map(|s| s.to_string());\n+\n+    Some(EntityData {\n+        title,\n+        author,\n+        body_html,\n+        thumb_url,\n+    })\n+}\n+\n+#[cfg(test)]\n+mod tests {\n+    use super::*;\n+\n+    #[test]\n+    fn map_subreddit_about_url() {\n+        let id = ItemId::parse(\"reddit.com/r/rust\").unwrap();\n+        assert_eq!(\n+            map_item_to_reddit_api(&id, false),\n+            \"https://www.reddit.com/r/rust/about.json?raw_json=1\"\n+        );\n+        assert_eq!(\n+            map_item_to_reddit_api(&id, true),\n+            \"https://oauth.reddit.com/r/rust/about.json?raw_json=1\"\n+        );\n+    }\n+\n+    #[test]\n+    fn map_post_url() {\n+        let id =\n+            ItemId::parse(\"reddit.com/r/amitheasshole/comments/1trnvdl\").unwrap();\n+        assert_eq!(\n+            map_item_to_reddit_api(&id, false),\n+            \"https://www.reddit.com/r/amitheasshole/comments/1trnvdl.json?raw_json=1\"\n+        );\n+    }\n+\n+    #[test]\n+    fn map_non_reddit_empty() {\n+        let id = ItemId::opaque(\"example.com/foo\");\n+        assert!(map_item_to_reddit_api(&id, false).is_empty());\n+    }\n+\n+    #[test]\n+    fn parse_subreddit_fixture() {\n+        let json = r#\"{\"kind\":\"t5\",\"data\":{\"title\":\"Rust\",\"display_name\":\"rust\",\"public_description\":\"systems\"}}\"#;\n+        let entity = parse_reddit_json(\n+            &ItemId::parse(\"reddit.com/r/rust\").unwrap(),\n+            json.as_bytes(),\n+        )\n+        .unwrap();\n+        assert_eq!(entity.title, \"Rust\");\n+    }\n+\n+    #[test]\n+    fn parse_post_fixture() {\n+        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\"}}]}}]\"#;\n+        let entity = parse_reddit_json(\n+            &ItemId::parse(\"reddit.com/r/x/comments/abc\").unwrap(),\n+            json.as_bytes(),\n+        )\n+        .unwrap();\n+        assert_eq!(entity.title, \"AITA\");\n+        assert_eq!(entity.author.as_deref(), Some(\"op\"));\n+    }\n }\ndiff --git a/server/src/state.rs b/server/src/state.rs\nindex cc1722f5a5bf4d415f2327ea585c488a15a75592..8c03aa60c15aee803a534439400b69935b1a3d84 100644\n--- a/server/src/state.rs\n+++ b/server/src/state.rs\n@@ -5,9 +5,10 @@ use tokio::sync::RwLock;\n use crate::{\n     event_log::EventLog,\n     events::Event,\n+    journal::JournalClient,\n     path_types::ItemId,\n+    reddit::{default_user_agent, RedditBroker},\n     reducer::{GlobalTree, VoteData},\n-    journal::JournalClient,\n     views::ViewStore,\n };\n \n@@ -73,6 +74,7 @@ pub struct AppState {\n     pub views: ViewStore,\n     pub tree: Arc<RwLock<GlobalTree>>,\n     journal: JournalClient,\n+    pub reddit: RedditBroker,\n }\n \n impl AppState {\n@@ -112,6 +114,7 @@ impl AppState {\n \n         let tree = Arc::new(RwLock::new(tree));\n         let journal = JournalClient::spawn(tree.clone(), event_log.clone());\n+        let reddit = RedditBroker::spawn(tree.clone(), &default_user_agent());\n \n         Self {\n             cfg: Arc::new(cfg),\n@@ -119,6 +122,7 @@ impl AppState {\n             views,\n             tree,\n             journal,\n+            reddit,\n         }\n     }\n \n@@ -127,8 +131,11 @@ impl AppState {\n             id: id.as_str().to_string(),\n         };\n         self.event_log.append(&event).await.map_err(|e| e.to_string())?;\n-        let mut w = self.tree.write().await;\n-        w.ensure_path(id);\n+        {\n+            let mut w = self.tree.write().await;\n+            w.ensure_path(id);\n+        }\n+        self.reddit.request_fetch(id.clone());\n         Ok(())\n     }\n \ndiff --git a/todo b/todo\nnew file mode 100644\nindex 0000000000000000000000000000000000000000..d196e8cb4cc80ccb95eeff01c73607d520e13212\n--- /dev/null\n+++ b/todo\n@@ -0,0 +1,7 @@\n+reddit import (only on explicit request)\n+reddit rendering\n+vote redering\n+pair chosing\n+nsfw gate\n+\n+logins (uuid user, two sides, oauths, and pseudonyms)\n\n\nSide B — contributor: tommy-mor\nSide B — commit message:\n[07715165] nice\n\nSide B — unified diff (full patch):\ndiff --git a/server/src/api/ui_html.rs b/server/src/api/ui_html.rs\nindex c3c62a76f424010d77a6090c84dd0b82098f573e..da2536112faea313352624cf2ce0ddd0ab3377c1 100644\n--- a/server/src/api/ui_html.rs\n+++ b/server/src/api/ui_html.rs\n@@ -6,7 +6,7 @@ use axum::{\n use std::collections::HashMap;\n \n use crate::{\n-    html::{demo_counter_panel, js_string_literal, ranking_panel, JsBuilder},\n+    html::{js_string_literal, ranking_panel, JsBuilder},\n     parser::parse_reddit_url,\n     parser_render::parser_panel_morph,\n     state::AppState,\n@@ -35,13 +35,6 @@ pub async fn post_ui_html(\n     };\n \n     match action {\n-        HtmlUiAction::BumpDemoCounter => {\n-            let count = state.bump_demo_counter().await;\n-            let panel = demo_counter_panel(count, state.event_log.path().to_string_lossy().as_ref());\n-            JsBuilder::new()\n-                .morph_selector(\"#demo-counter-panel\", panel)\n-                .into_response()\n-        }\n         HtmlUiAction::RecordVote {\n             a,\n             b,\n@@ -54,8 +47,8 @@ pub async fn post_ui_html(\n             {\n                 return ui_js_warn(&e).into_response();\n             }\n-            let mut group = state.group.write().await;\n-            let panel = ranking_panel(&mut group);\n+            let group = state.group.read().await;\n+            let panel = ranking_panel(&group);\n             JsBuilder::new()\n                 .morph_selector(\"#ranking-panel\", panel)\n                 .into_response()\n@@ -87,20 +80,6 @@ mod tests {\n         assert!(matches!(err, HtmlUiParseError::MissingRpc));\n     }\n \n-    #[test]\n-    fn bump_action_deserializes() {\n-        let template = serde_json::json!({ \"action\": \"bump_demo_counter\" });\n-        let mut form = HashMap::new();\n-        form.insert(\n-            UI_RPC_FIELD.to_string(),\n-            serde_json::to_string(&template).unwrap(),\n-        );\n-        assert_eq!(\n-            parse_html_ui_from_form(&form).unwrap(),\n-            HtmlUiAction::BumpDemoCounter\n-        );\n-    }\n-\n     #[test]\n     fn record_vote_action_deserializes() {\n         let template = serde_json::json!({\ndiff --git a/server/src/events.rs b/server/src/events.rs\nindex b969242534e184d4f0a689543a479670b08a18df..eff80aef0257f706d2341f666e63d6a3d921bf6e 100644\n--- a/server/src/events.rs\n+++ b/server/src/events.rs\n@@ -5,8 +5,6 @@ use serde::{Deserialize, Serialize};\n pub enum Event {\n     /// Page view recorded (path → counter in views.json).\n     ViewRecorded { path: String, ts: i64 },\n-    /// Demo counter bump from `POST /ui` (persisted in the single JSONL log).\n-    DemoCounterBumped { ts: i64, value: u64 },\n     /// Pairwise comparison vote (replayed into [`crate::reducer::GroupState`] on boot).\n     VoteRecorded {\n         ts: i64,\ndiff --git a/server/src/html/mod.rs b/server/src/html/mod.rs\nindex 5b1d0b5a887d89e7e80796aa7a6c8ed5baaf2782..d69ed962b5c8625bc83c933b1825f2cc1d0868e2 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     parser_action::ParserAction,\n     parser_render::parser_panel,\n-    ranking::ranked_items,\n+    ranking::ranked_items_cached,\n     reducer::GroupState,\n     state::AppState,\n     ui_action::UI_RPC_FIELD,\n@@ -199,10 +199,8 @@ fn layout(title: &str, body: Markup, views: u64, theme: &str, theme_next: &str)\n     }\n }\n \n-pub fn ranking_panel(group: &mut GroupState) -> Markup {\n-    const MAX_ITERS: usize = 10_000;\n-    const TOL: f64 = 1e-8;\n-    let items = ranked_items(group, MAX_ITERS, TOL);\n+pub fn ranking_panel(group: &GroupState) -> Markup {\n+    let items = ranked_items_cached(group);\n     html! {\n         section id=\"ranking-panel\" class=\"demo-panel\" {\n             h2 { \"Ranking\" }\n@@ -260,35 +258,6 @@ pub fn vote_panel() -> Markup {\n }\n \n \n-pub fn demo_counter_panel(count: u64, event_log_path: &str) -> Markup {\n-    let rpc = template_json_compact(&serde_json::json!({ \"action\": \"bump_demo_counter\" }))\n-        .expect(\"rpc json\");\n-    html! {\n-        section id=\"demo-counter-panel\" class=\"demo-panel\" {\n-            h1 { \"sorter2\" }\n-            p class=\"muted\" {\n-                \"Pairwise ranking scaffold — votes persist to JSONL and replay on boot.\"\n-            }\n-            p class=\"demo-count\" {\n-                strong { \"Counter: \" }\n-                span id=\"demo-count-value\" { (count) }\n-            }\n-            p class=\"muted small\" {\n-                \"Event log: \" code { (event_log_path) }\n-            }\n-            form method=\"post\" action=\"/ui\" id=\"demo-bump-form\" {\n-                input type=\"hidden\" name=(UI_RPC_FIELD) value=(rpc);\n-                button type=\"submit\" class=\"btn-primary\" { \"Bump (POST /ui → eval JS)\" }\n-            }\n-            p class=\"muted small\" {\n-                \"Uses hidden \"\n-                code { \"__rpc__\" }\n-                \" JSON + Idiomorph morph — no full page reload.\"\n-            }\n-        }\n-    }\n-}\n-\n pub async fn home(\n     State(state): State<AppState>,\n     jar: CookieJar,\n@@ -297,16 +266,15 @@ pub async fn home(\n     let path = uri.path().to_string();\n     state.views.increment(path.clone());\n     let views = state.views.get_views(&path);\n-    let count = *state.demo_counter.read().await;\n     let theme = theme_from_jar(&jar);\n     let theme_next = theme_next_from_uri(&uri);\n-    let mut group = state.group.write().await;\n+    let group = state.group.read().await;\n     let empty_action = ParserAction::suggest(String::new(), None);\n     let body = html! {\n+        h1 { \"sorter2\" }\n         (parser_panel(\"\", &empty_action))\n         (vote_panel())\n-        (ranking_panel(&mut group))\n-        (demo_counter_panel(count, state.event_log.path().to_string_lossy().as_ref()))\n+        (ranking_panel(&group))\n     };\n     layout(\"sorter2\", body, views, theme, &theme_next)\n }\ndiff --git a/server/src/lib.rs b/server/src/lib.rs\nindex 6716c5b282e7980a7a0f03d63ad8b25eda61cc55..fa423640d598f4ba97a5885d228e78d7b97f7a22 100644\n--- a/server/src/lib.rs\n+++ b/server/src/lib.rs\n@@ -9,6 +9,7 @@ pub mod parser_render;\n pub mod path_types;\n pub mod ranking;\n pub mod reducer;\n+pub mod settlement;\n pub mod state;\n pub mod ui_action;\n pub mod views;\ndiff --git a/server/src/ranking.rs b/server/src/ranking.rs\nindex 89d3280126a8d8f841721ce8cb63ff735d68752a..2d706762792ba9239bb3f1c2e4974a2fde908013 100644\n--- a/server/src/ranking.rs\n+++ b/server/src/ranking.rs\n@@ -91,6 +91,11 @@ pub fn compute_group_ranking(group: &mut GroupState, max_iters: usize, tol: f64)\n \n pub fn ranked_items(group: &mut GroupState, max_iters: usize, tol: f64) -> Vec<RankedItem> {\n     compute_group_ranking(group, max_iters, tol);\n+    ranked_items_cached(group)\n+}\n+\n+/// Read cached scores without recomputing (HTTP fast path).\n+pub fn ranked_items_cached(group: &GroupState) -> Vec<RankedItem> {\n     let mut items: Vec<RankedItem> = group\n         .idx_to_item\n         .iter()\n@@ -105,7 +110,12 @@ pub fn ranked_items(group: &mut GroupState, max_iters: usize, tol: f64) -> Vec<R\n     items\n }\n \n-fn compute_scores_from_edges(n: usize, edges: impl Iterator<Item = ((usize, usize), f64)>, max_iters: usize, tol: f64) -> Vec<f64> {\n+pub fn compute_scores_from_edges(\n+    n: usize,\n+    edges: impl Iterator<Item = ((usize, usize), f64)>,\n+    max_iters: usize,\n+    tol: f64,\n+) -> Vec<f64> {\n     if n == 0 {\n         return vec![];\n     }\ndiff --git a/server/src/settlement.rs b/server/src/settlement.rs\nnew file mode 100644\nindex 0000000000000000000000000000000000000000..1f722ceaea62cda22c28ab71551f259fbf049b81\n--- /dev/null\n+++ b/server/src/settlement.rs\n@@ -0,0 +1,114 @@\n+use std::sync::Arc;\n+\n+use tokio::sync::{mpsc, oneshot, RwLock};\n+\n+use crate::{\n+    event_log::EventLog,\n+    events::Event,\n+    ranking::compute_scores_from_edges,\n+    reducer::{GroupState, VoteData},\n+};\n+\n+const MAX_ITERS: usize = 10_000;\n+const TOL: f64 = 1e-8;\n+\n+pub struct SettlementCommand {\n+    pub vote: VoteData,\n+    pub event: Event,\n+    pub reply: oneshot::Sender<Result<(), String>>,\n+}\n+\n+#[derive(Clone)]\n+pub struct SettlementClient {\n+    tx: mpsc::Sender<SettlementCommand>,\n+}\n+\n+impl SettlementClient {\n+    pub fn spawn(group: Arc<RwLock<GroupState>>, event_log: Arc<EventLog>) -> Self {\n+        let (tx, rx) = mpsc::channel(64);\n+        tokio::spawn(settlement_worker(rx, group, event_log));\n+        Self { tx }\n+    }\n+\n+    pub async fn record_vote(&self, vote: VoteData, event: Event) -> Result<(), String> {\n+        let (reply, rx) = oneshot::channel();\n+        self.tx\n+            .send(SettlementCommand {\n+                vote,\n+                event,\n+                reply,\n+            })\n+            .await\n+            .map_err(|_| \"settlement worker stopped\".to_string())?;\n+        rx.await\n+            .map_err(|_| \"settlement worker stopped\".to_string())?\n+    }\n+}\n+\n+async fn settlement_worker(\n+    mut rx: mpsc::Receiver<SettlementCommand>,\n+    group: Arc<RwLock<GroupState>>,\n+    event_log: Arc<EventLog>,\n+) {\n+    while let Some(first) = rx.recv().await {\n+        let mut batch = vec![first];\n+        while let Ok(more) = rx.try_recv() {\n+            batch.push(more);\n+        }\n+\n+        let mut disk_err: Option<String> = None;\n+        for cmd in &batch {\n+            if let Err(e) = event_log.append(&cmd.event).await {\n+                disk_err = Some(e.to_string());\n+                break;\n+            }\n+        }\n+\n+        if let Some(err) = disk_err {\n+            for cmd in batch {\n+                let _ = cmd.reply.send(Err(err.clone()));\n+            }\n+            continue;\n+        }\n+\n+        let (edges, n) = {\n+            let mut w = group.write().await;\n+            for cmd in &batch {\n+                w.apply_vote(cmd.vote.clone());\n+            }\n+            (w.edges.clone(), w.idx_to_item.len())\n+        };\n+\n+        let new_scores = compute_scores_from_edges(\n+            n,\n+            edges.iter().map(|(&k, &v)| (k, v)),\n+            MAX_ITERS,\n+            TOL,\n+        );\n+\n+        {\n+            let mut w = group.write().await;\n+            w.cached_scores = new_scores;\n+            w.dirty = false;\n+        }\n+\n+        for cmd in batch {\n+            let _ = cmd.reply.send(Ok(()));\n+        }\n+    }\n+}\n+\n+/// Compute ranking cache from current in-memory edges (startup replay only).\n+pub fn warm_ranking_cache(group: &mut GroupState) {\n+    if !group.dirty {\n+        return;\n+    }\n+    let n = group.idx_to_item.len();\n+    group.cached_scores = compute_scores_from_edges(\n+        n,\n+        group.edges.iter().map(|(&k, &v)| (k, v)),\n+        MAX_ITERS,\n+        TOL,\n+    );\n+    group.dirty = false;\n+}\ndiff --git a/server/src/state.rs b/server/src/state.rs\nindex 8ec9902e2ecc31cf8208f7ad6365891dc5537eed..1922541a4064c2de1df2d993a461cae783320e05 100644\n--- a/server/src/state.rs\n+++ b/server/src/state.rs\n@@ -6,6 +6,7 @@ use crate::{\n     event_log::EventLog,\n     events::Event,\n     reducer::{GroupState, VoteData},\n+    settlement::{warm_ranking_cache, SettlementClient},\n     views::ViewStore,\n };\n \n@@ -38,8 +39,8 @@ pub struct AppState {\n     pub cfg: Arc<AppConfig>,\n     pub event_log: Arc<EventLog>,\n     pub views: ViewStore,\n-    pub demo_counter: Arc<RwLock<u64>>,\n     pub group: Arc<RwLock<GroupState>>,\n+    settlement: SettlementClient,\n }\n \n impl AppState {\n@@ -48,14 +49,10 @@ impl AppState {\n         let views_path = format!(\"{}/views.json\", cfg.data_dir);\n         let views = ViewStore::new(&views_path);\n \n-        let mut demo_counter: u64 = 0;\n         let mut group = GroupState::new();\n         if let Ok((events, _)) = event_log.load_all().await {\n             for ev in events {\n                 match ev {\n-                    Event::DemoCounterBumped { value, .. } => {\n-                        demo_counter = demo_counter.max(value);\n-                    }\n                     Event::VoteRecorded {\n                         ts,\n                         a,\n@@ -74,30 +71,20 @@ impl AppState {\n             }\n         }\n \n+        warm_ranking_cache(&mut group);\n+\n+        let group = Arc::new(RwLock::new(group));\n+        let settlement = SettlementClient::spawn(group.clone(), event_log.clone());\n+\n         Self {\n             cfg: Arc::new(cfg),\n             event_log,\n             views,\n-            demo_counter: Arc::new(RwLock::new(demo_counter)),\n-            group: Arc::new(RwLock::new(group)),\n+            group,\n+            settlement,\n         }\n     }\n \n-    pub async fn bump_demo_counter(&self) -> u64 {\n-        let mut guard = self.demo_counter.write().await;\n-        *guard += 1;\n-        let value = *guard;\n-        drop(guard);\n-\n-        let ts = crate::html::now_ms();\n-        let _ = self\n-            .event_log\n-            .append(&Event::DemoCounterBumped { ts, value })\n-            .await;\n-\n-        value\n-    }\n-\n     pub async fn record_vote(\n         &self,\n         a: &str,\n@@ -109,23 +96,14 @@ impl AppState {\n         let vote = VoteData::from_recorded(ts, a, b, ratio_left, ratio_right)\n             .ok_or_else(|| \"invalid vote: need two distinct non-empty items\".to_string())?;\n \n-        {\n-            let mut group = self.group.write().await;\n-            group.apply_vote(vote.clone());\n-        }\n-\n-        let _ = self\n-            .event_log\n-            .append(&Event::VoteRecorded {\n-                ts,\n-                a: vote.a.as_str().to_string(),\n-                b: vote.b.as_str().to_string(),\n-                ratio_left: vote.ratio_left,\n-                ratio_right: vote.ratio_right,\n-            })\n-            .await\n-            .map_err(|e| e.to_string())?;\n+        let event = Event::VoteRecorded {\n+            ts,\n+            a: vote.a.as_str().to_string(),\n+            b: vote.b.as_str().to_string(),\n+            ratio_left: vote.ratio_left,\n+            ratio_right: vote.ratio_right,\n+        };\n \n-        Ok(())\n+        self.settlement.record_vote(vote, event).await\n     }\n }\ndiff --git a/server/src/ui_action.rs b/server/src/ui_action.rs\nindex 1d488e1ad1d8fd81bd9d016d69255adfe9b22fc8..5d94c84113607b3bcd8d31d03ef5b8e1b87b67a7 100644\n--- a/server/src/ui_action.rs\n+++ b/server/src/ui_action.rs\n@@ -12,8 +12,6 @@ pub const UI_RPC_FIELD: &str = \"__rpc__\";\n #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]\n #[serde(tag = \"action\", rename_all = \"snake_case\")]\n pub enum HtmlUiAction {\n-    /// Demo: morph `#demo-counter-panel` after bumping the persisted counter.\n-    BumpDemoCounter,\n     /// Record a pairwise vote and morph `#ranking-panel`.\n     RecordVote {\n         a: String,\n@@ -52,18 +50,6 @@ pub fn parse_html_ui_from_form(\n mod tests {\n     use super::*;\n \n-    #[test]\n-    fn bump_demo_counter_round_trip() {\n-        let template = serde_json::json!({ \"action\": \"bump_demo_counter\" });\n-        let mut form = HashMap::new();\n-        form.insert(\n-            UI_RPC_FIELD.to_string(),\n-            serde_json::to_string(&template).unwrap(),\n-        );\n-        let a = parse_html_ui_from_form(&form).unwrap();\n-        assert_eq!(a, HtmlUiAction::BumpDemoCounter);\n-    }\n-\n     #[test]\n     fn record_vote_round_trip_with_form_holes() {\n         let template = serde_json::json!({\ndiff --git a/server/tests/integration_health.rs b/server/tests/integration_health.rs\nindex 8a58bc14aac68c779e7ce4ffa57d27b3220e9953..1d816e008b9bf629967e3b3c786c41afefc284e3 100644\n--- a/server/tests/integration_health.rs\n+++ b/server/tests/integration_health.rs\n@@ -38,7 +38,7 @@ async fn healthz_ok() {\n }\n \n #[tokio::test]\n-async fn home_has_demo_panel() {\n+async fn home_has_main_panels() {\n     let (addr, _tmp) = start_test_server().await;\n     let client = reqwest::Client::new();\n     let html = client\ndiff --git a/server/tests/integration_ui.rs b/server/tests/integration_ui.rs\nindex bee79407dec120699a083f1a75adf9291e207fc7..7ede46d681fefbe25b1d98fc33520a185515eb1c 100644\n--- a/server/tests/integration_ui.rs\n+++ b/server/tests/integration_ui.rs\n@@ -25,33 +25,6 @@ async fn start_test_server() -> (SocketAddr, TempDir) {\n     (addr, tmp)\n }\n \n-#[tokio::test]\n-async fn post_ui_bump_returns_javascript_morph() {\n-    let (addr, tmp) = start_test_server().await;\n-    let rpc = serde_json::json!({ \"action\": \"bump_demo_counter\" }).to_string();\n-    let mut form = HashMap::new();\n-    form.insert(UI_RPC_FIELD.to_string(), rpc);\n-\n-    let client = reqwest::Client::new();\n-    let body = client\n-        .post(format!(\"http://{addr}/ui\"))\n-        .form(&form)\n-        .send()\n-        .await\n-        .unwrap()\n-        .text()\n-        .await\n-        .unwrap();\n-\n-    assert!(body.contains(\"Idiomorph.morph\"));\n-    assert!(body.contains(\"demo-counter-panel\"));\n-    assert!(body.contains(\"Counter:\"));\n-\n-    let log_path = tmp.path().join(\"events.jsonl\");\n-    let log = std::fs::read_to_string(log_path).unwrap();\n-    assert!(log.contains(\"demo_counter_bumped\"));\n-}\n-\n #[tokio::test]\n async fn post_ui_record_vote_morphs_ranking_and_persists() {\n     let (addr, tmp) = start_test_server().await;\n@@ -90,8 +63,8 @@ async fn post_ui_record_vote_morphs_ranking_and_persists() {\n         port: 0,\n     };\n     let state = create_app_state(cfg).await;\n-    let mut group = state.group.write().await;\n-    let ranked = sorter2_server::ranking::ranked_items(&mut group, 10_000, 1e-8);\n+    let group = state.group.read().await;\n+    let ranked = sorter2_server::ranking::ranked_items_cached(&group);\n     assert_eq!(ranked.len(), 2);\n     assert_eq!(ranked[0].item.as_str(), \"alpha\");\n }\ndiff --git a/test/smoke.clj b/test/smoke.clj\nindex b332324743b58baf3fe96d7477353749f137feae..11887c48282088e140d823a88ba616f6325835b3 100644\n--- a/test/smoke.clj\n+++ b/test/smoke.clj\n@@ -26,7 +26,7 @@\n             false))))))\n \n (deftest http-smoke-against-running-server\n-  (testing \"build, start, healthz, home contains RPC demo\"\n+  (testing \"build, start, healthz, home contains main panels\"\n     (let [root (repo-root)\n           data-dir (.getAbsolutePath (doto (io/file (System/getProperty \"java.io.tmpdir\")\n                                                    (str \"sorter2-smoke-\" (System/currentTimeMillis)))\n","role":"user"}],"model":"~anthropic/claude-sonnet-latest"}