feat: in-reader settings, more like this, reading history, audio filter, feed page

- Add floating gear button + theme/font/size drawer in chapter reader
- Add 'More like this' horizontal scroll row on book detail page
- Add reading history tab on profile page (chronological progress timeline)
- Add audio-available badge + filter toggle on catalogue (GET /api/audio/slugs)
- Fix discover card entry animation pop (split entry vs snap-back cubic-bezier)
- Add dedicated /feed page showing books followed users are reading
- Add Feed nav link (desktop + mobile) in all 5 locales

ui/src/lib/server/pocketbase.ts

@@ -1034,6 +1034,15 @@ export async function listAudioJobs(): Promise<AudioJob[]> {
 	return listAll<AudioJob>('audio_jobs', '', '-started');
 }
 
+/**
+ * Returns the set of book slugs that have at least one completed audio job.
+ * Used by the catalogue page to show audio-available badges.
+ */
+export async function getSlugsWithAudio(): Promise<Set<string>> {
+	const jobs = await listAll<AudioJob>('audio_jobs', 'status="done"', 'slug');
+	return new Set(jobs.map((j) => j.slug));
+}
+
 // ─── Translation jobs ─────────────────────────────────────────────────────────
 
 export interface TranslationJob {