feat: always-on Insights — correlation analysis over viewing habits

Conservative, live insights (ADR-0010) derived from each user's diary:
rating lift by genre (first-time watches only), genre seasonality vs a
uniform 1/12 month baseline, medium weekend-lift, and watch-time rhythm.

- domain: WatchRow model, InsightsQuery port, pure insights_analyzer with
  all honesty thresholds (sample minimums, strength cutoffs, suppressions
  for import noise), unit-tested
- adapters: thin Sqlite/Postgres fetch twins, reusing WrapUp's genre fetch
- application: get_insights use case, InsightsGroup in Deps
- composition/server: wiring through Repositories/DatabaseOutput
- presentation: GET /api/v1/insights handler, typed serde-tagged DTOs,
  openapi doc
- spa: /insights route (shadcn cards), insights feature hook, profile
  entry link, en locale strings
- server test: end-to-end seed sqlite → HTTP → rating lift + rhythm

Also records ADR-0010, defines "Insight" in the glossary, and includes
pre-existing worktree comment-stripping cleanups.

crates/adapters/image-converter/src/backfill.rs

@@ -27,7 +27,7 @@ impl ConversionBackfillJob {
 #[async_trait]
 impl PeriodicJob for ConversionBackfillJob {
     fn interval(&self) -> Duration {
-        Duration::from_secs(60 * 60 * 24) // 24h
+        Duration::from_secs(60 * 60 * 24)
     }
 
     async fn run(&self) -> Result<(), DomainError> {

crates/adapters/image-converter/src/tests/handler.rs

@@ -130,8 +130,6 @@ async fn converts_jpeg_to_avif_and_swaps_key() {
         vec![("avatars/u1".into(), "avatars/u1.avif".into())]
     );
     assert!(storage.get("avatars/u1.avif").await.is_ok());
-    // Old raw key deleted — fallback resolves to .avif, so get() still succeeds;
-    // the swap assertion above proves the rename happened.
 }
 
 #[tokio::test]