Reuse an existing category's spelling in the categorizer; document the Interests page (step 9)

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K9PrjtUS16PAQve8D4bHgc

README.md

@@ -214,7 +214,10 @@ sees complete issues and article chapters and can download available formats
 from a single download menu. An
 `admin` can additionally follow direct dashboard links from issue entries and
 article chapters, rate articles, and use every `/dashboard/*` page, including
-settings and jobs. Personalization is shared across accounts for now.
+settings and jobs. `/dashboard/interests` lists the standing interests with
+their LLM-assigned category and a rating-derived weight, adds or deletes them,
+and links every interest name in the UI to the articles it matched.
+Personalization is shared across accounts for now.
 
 Visitors can request an account with their preferred username at
 `/request-access`; admins review open requests on `/dashboard/users`. Approving
@@ -250,6 +253,7 @@ Set `server.jobs_enabled = false` to make starts unavailable.
 | `backfill-social` | Refresh recent social scores. |
 | `features-prune` | Remove stale embeddings and curation telemetry. |
 | `import-ratings` | Fetch, embed, and rate URLs queued from the Ratings page. |
+| `interests-categorize` | File uncategorized interests under categories with the bulk model. |
 
 The Ratings page accepts up to 500 historical article URLs at a time with one
 verdict and optional note. Imports run in the background and show per-URL

src/interests.rs

@@ -354,8 +354,8 @@ async fn categorize_with_llm(db: &Db, pending: &[Interest], llm: &LlmClient) ->
         .collect::<HashMap<_, _>>();
     let existing_categories = categories
         .iter()
-        .map(|category| category.to_lowercase())
-        .collect::<BTreeSet<_>>();
+        .map(|category| (category.to_lowercase(), *category))
+        .collect::<HashMap<_, _>>();
     let mut assigned = BTreeSet::new();
     let mut new_categories = BTreeSet::new();
     let now = Timestamp::now();
@@ -367,10 +367,16 @@ async fn categorize_with_llm(db: &Db, pending: &[Interest], llm: &LlmClient) ->
         if !(1..=60).contains(&category.chars().count()) || !assigned.insert(interest.id) {
             continue;
         }
-        set_category(db, interest.id, Some(category), now).await?;
-        if !existing_categories.contains(&category.to_lowercase()) {
+        // A model that answers "software" for an existing "Software" must not
+        // split the category.
+        let category = match existing_categories.get(&category.to_lowercase()) {
+            Some(existing) => existing,
+            None => {
                 new_categories.insert(category.to_string());
+                category
             }
+        };
+        set_category(db, interest.id, Some(category), now).await?;
     }
 
     let mut message = format!(
@@ -750,7 +756,7 @@ mod tests {
         let backend = Arc::new(MockBackend::new());
         backend.push(
             r#"{"assignments":[
-                {"interest":"RUST MACROS","category":" Software "},
+                {"interest":"RUST MACROS","category":" software "},
                 {"interest":"Wheel-thrown pottery","category":"Creative crafts"},
                 {"interest":"Not in the batch","category":"Made up"}
             ]}"#,