Web dashboard step 4: ratings page and profile editor

Add /dashboard/ratings with the preference-state header, the "How ratings
enter the algorithm" explainer, the Current tab (decayed neighbour weight,
feed credit, prompt/rebuild membership, last-run neighbour usage, inline
rating widget with note) and the paginated, filterable Events tab with
superseded marking.

Add /dashboard/profile: profile.md editor with atomic mode-preserving
writes and profile_versions history plus restore, the parsed preview,
OPML interests by theme, learned adjustments with staleness, the stored
system prompt, and the profile-rebuild job form.

Make profile::MAX_RATINGS_IN_REBUILD and profile::stored_version pub.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NHyYupFdBiR4VfoUM7NjSM

src/curate/profile/mod.rs

@@ -21,7 +21,7 @@ pub const REBUILD_INTERVAL_DAYS: i64 = 7;
 /// so their `current_ratings` lookback is effectively unbounded.
 const RATINGS_LOOKBACK_DAYS: i64 = 36_500;
 pub const KV_LEARNED_ADJUSTMENTS: &str = "taste_profile_learned";
-const MAX_RATINGS_IN_REBUILD: usize = 200;
+pub const MAX_RATINGS_IN_REBUILD: usize = 200;
 
 pub const NO_LEARNED_ADJUSTMENTS: &str = "No reader ratings have been collected yet. Judge purely on the stated preferences and interests above.";
 
@@ -239,7 +239,9 @@ struct ProfileVersion {
     built_at: String,
 }
 
-async fn stored_version(db: &Db) -> anyhow::Result<Option<(i64, Timestamp)>> {
+/// The stored `(version, built_at)` of the taste profile, `None` before the
+/// first build. The dashboard's profile page reads it (web plan §11).
+pub async fn stored_version(db: &Db) -> anyhow::Result<Option<(i64, Timestamp)>> {
     let Some(raw) = db.kv_get(KV_PROFILE_VERSION).await? else {
         return Ok(None);
     };