spa hardening, offline logging, rate limit fixes

server:
- backup exporter, auth extractors, error shapes, CONTEXT (prior work)
- spa assets served outside the rate limit via route_layer
- requests_per_second went to per_second(), which takes an interval not a
  rate: 50 meant one request per 50s once burst was spent. now converted
  properly. 15/s, burst 60

spa fixes:
- account delete cleared snake_case token keys that were never written
- refresh interceptor could retry forever
- date ranges used local day boundaries stamped +00:00
- "all" period trend plotted one page; calendar days fabricated mood 3
- chart grid invisible: hsl(var(--border)) against rgba tokens
- blob url leak, orphaned media on failed save, devtools in prod bundle
- pt-safe/safe-area-pb classes never existed

spa features:
- offline outbox: entries queue to IndexedDB, replay with backoff, only
  server refusals count against an entry
- drafts persist, quick-log sheet, diary infinite scroll + filters
- route error boundary, stale-chunk recovery, no service worker in dev

a11y + perf:
- mood picker is a radiogroup, activity picker keyboard-operable,
  text alternatives for colour/emoji, locale week start
- dark glass over the bright photo: worst case 1.4:1 -> 4.9-9.6:1
- initial payload 1095->769kB raw, 306->230kB gzip; 38 unused components
  and 5 deps dropped; fonts 218->133kB

53 tests added (43 spa, 10 server)

crates/adapters/sqlite/src/repositories/job/backfill.rs

@@ -48,6 +48,24 @@ impl domain::ports::RecordingBackfillQueryPort for SqliteRecordingBackfillReposi
         Ok(rows.iter().filter_map(readable).collect())
     }
 
+    async fn find_song_without_a_recording(
+        &self,
+        entry_id: &MoodEntryId,
+    ) -> Result<Option<UnidentifiedSong>, DomainError> {
+        let row: Option<UnidentifiedSongRow> = sqlx::query_as(
+            "SELECT s.entry_id, e.user_id, s.title, s.artist
+             FROM entry_song s
+             JOIN mood_entries e ON e.id = s.entry_id
+             WHERE s.recording_id IS NULL AND s.entry_id = ?",
+        )
+        .bind(entry_id.value().to_string())
+        .fetch_optional(&self.pool)
+        .await
+        .map_err(db_err)?;
+
+        Ok(row.as_ref().and_then(readable))
+    }
+
     async fn record_identity(
         &self,
         entry_id: &MoodEntryId,