feat(translation): machine translation pipeline + admin bulk enqueue UI

- LibreTranslate client (chunks on blank lines, ≤4500 chars, 3-goroutine semaphore)
- Runner translation task loop (OTel, heartbeat, MinIO storage)
- PocketBase translation_jobs collection support (create/claim/finish/list)
- Per-chapter language switcher on chapter reader (EN/RU/ID/PT/FR, polls until done)
- Admin /admin/translation page: bulk enqueue form + live-polling jobs table
- New backend routes: POST /api/translation/{slug}/{n}, GET /api/translation/status,
  GET /api/translation/{slug}/{n}, GET /api/admin/translation/jobs,
  POST /api/admin/translation/bulk
- ListTranslationTasks added to taskqueue.Reader interface + store impl
- All builds and tests pass; svelte-check: 0 errors

ui/src/lib/server/pocketbase.ts

@@ -917,6 +917,24 @@ export async function listAudioJobs(): Promise<AudioJob[]> {
 	return listAll<AudioJob>('audio_jobs', '', '-started');
 }
 
+// ─── Translation jobs ─────────────────────────────────────────────────────────
+
+export interface TranslationJob {
+	id: string;
+	cache_key: string; // "slug/chapter/lang"
+	slug: string;
+	chapter: number;
+	lang: string;
+	status: string; // "pending" | "running" | "done" | "failed"
+	error_message: string;
+	started: string;
+	finished: string;
+}
+
+export async function listTranslationJobs(): Promise<TranslationJob[]> {
+	return listAll<TranslationJob>('translation_jobs', '', '-started');
+}
+
 export async function getAudioTime(
 	sessionId: string,
 	slug: string,