Add /admin/audio-jobs page for audio generation job history

New page mirrors the scrape tasks pattern: loads audio_jobs from
PocketBase via a new listAudioJobs() helper, shows a filterable table
(slug, chapter, voice, status, started, duration, error), and live-polls
every 3s while any job is pending or generating. Also fixes the
/admin/audio nav active-state check (was startsWith, now exact match)
to prevent it from matching /admin/audio-jobs.

ui/src/lib/server/pocketbase.ts

@@ -657,6 +657,24 @@ export async function listScrapingTasks(): Promise<ScrapingTask[]> {
 	return listAll<ScrapingTask>('scraping_tasks', '', '-started');
 }
 
+// ─── Audio jobs ───────────────────────────────────────────────────────────────
+
+export interface AudioJob {
+	id: string;
+	cache_key: string; // "slug/chapter/voice"
+	slug: string;
+	chapter: number;
+	voice: string;
+	status: string; // "pending" | "generating" | "done" | "failed"
+	error_message: string;
+	started: string;
+	finished: string;
+}
+
+export async function listAudioJobs(): Promise<AudioJob[]> {
+	return listAll<AudioJob>('audio_jobs', '', '-started');
+}
+
 export async function getAudioTime(
 	sessionId: string,
 	slug: string,