feat(podcast): add podcast RSS feed generation and publishing

Admins can now generate TTS audiobooks chapter-by-chapter and publish
them as standard RSS 2.0 + iTunes podcast feeds that Spotify, Apple
Podcasts, and any podcast app can subscribe to.

Backend:
- POST /api/admin/podcast — creates ai_job (kind=podcast), spawns
  goroutine that generates TTS for missing chapters and writes to MinIO
- GET /podcast/{slug}.xml?voice=<id> — public RSS feed with correct
  pubDate (from chapters_idx.created) and enclosure length (MinIO stat)
- GET /podcast/audio/{slug}/{n}/{voice} — public audio proxy, 302 to
  presigned MinIO URL (no auth required for podcast clients)
- GET /api/admin/podcast/{slug} — list podcast jobs for a book
- Add AudioObjectSize to AudioStore interface backed by MinIO StatObject
- Populate ChapterInfo.Date from chapters_idx.created in ListChapters

UI:
- New /admin/podcast page: book + voice selector, chapter range, live
  progress bars, copy-feed-URL button, cancel button, how-to instructions
- /api/admin/podcast SvelteKit proxy (injects admin Bearer token)
- Podcast link added to admin sidebar

Cleanup:
- Delete stray playwright screenshot files from repo root
- Add .playwright-mcp/ to .gitignore

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/src/routes/admin/+layout.svelte

@@ -49,6 +49,11 @@
 			label: () => m.admin_nav_catalogue_tools(),
 			icon: `<path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M19 11H5m14 0a2 2 0 012 2v6a2 2 0 01-2 2H5a2 2 0 01-2-2v-6a2 2 0 012-2m14 0V9a2 2 0 00-2-2M5 11V9a2 2 0 012-2m0 0V5a2 2 0 012-2h6a2 2 0 012 2v2M7 7h10" />`
 		},
+		{
+			href: '/admin/podcast',
+			label: () => 'Podcast',
+			icon: `<path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M19 11a7 7 0 01-7 7m0 0a7 7 0 01-7-7m7 7v4m0 0H8m4 0h4m-4-8a3 3 0 01-3-3V5a3 3 0 116 0v6a3 3 0 01-3 3z" />`
+		},
 		{
 			href: '/admin/changelog',
 			label: () => m.admin_nav_changelog(),

ui/src/routes/admin/podcast/+page.server.ts

@@ -0,0 +1,30 @@
+import type { PageServerLoad } from './$types';
+import { listBooks, listAIJobs, type Book, type AIJob } from '$lib/server/pocketbase';
+import { backendFetch } from '$lib/server/scraper';
+import { log } from '$lib/server/logger';
+
+export type { Book, AIJob };
+
+export const load: PageServerLoad = async () => {
+	const [books, allJobs, voicesRes] = await Promise.all([
+		listBooks().catch((e): Book[] => {
+			log.warn('admin/podcast', 'failed to load books', { err: String(e) });
+			return [];
+		}),
+		listAIJobs().catch((e): AIJob[] => {
+			log.warn('admin/podcast', 'failed to load ai jobs', { err: String(e) });
+			return [];
+		}),
+		backendFetch('/api/voices').catch(() => null)
+	]);
+
+	const podcastJobs = allJobs.filter((j) => j.kind === 'podcast');
+
+	let voices: { id: string; engine: string; lang: string; gender: string }[] = [];
+	if (voicesRes?.ok) {
+		const body = await voicesRes.json().catch(() => null);
+		if (Array.isArray(body?.voices)) voices = body.voices;
+	}
+
+	return { books, podcastJobs, voices };
+};

ui/src/routes/admin/podcast/+page.svelte

@@ -0,0 +1,312 @@
+<script lang="ts">
+	import { page } from '$app/state';
+	import type { PageData } from './$types';
+	import type { AIJob } from '$lib/server/pocketbase';
+
+	let { data }: { data: PageData } = $props();
+
+	// ── Form state ────────────────────────────────────────────────────────────────
+	let selectedSlug = $state('');
+	let selectedVoice = $state('');
+	let fromChapter = $state(0);
+	let toChapter = $state(0);
+	let busy = $state(false);
+	let error = $state('');
+	let successMsg = $state('');
+
+	// ── Job list ──────────────────────────────────────────────────────────────────
+	let jobs = $state<AIJob[]>(data.podcastJobs);
+
+	const hasInFlight = $derived(
+		jobs.some((j) => j.status === 'pending' || j.status === 'running')
+	);
+
+	// Auto-refresh while jobs are running.
+	$effect(() => {
+		if (!hasInFlight) return;
+		const id = setInterval(async () => {
+			const res = await fetch('/api/admin/ai-jobs').catch(() => null);
+			if (res?.ok) {
+				const body = await res.json().catch(() => null);
+				if (Array.isArray(body?.jobs)) {
+					jobs = (body.jobs as AIJob[]).filter((j) => j.kind === 'podcast');
+				}
+			}
+		}, 3000);
+		return () => clearInterval(id);
+	});
+
+	// ── Helpers ───────────────────────────────────────────────────────────────────
+	function statusColor(status: string) {
+		switch (status) {
+			case 'done': return 'text-green-400';
+			case 'running': return 'text-(--color-brand) animate-pulse';
+			case 'pending': return 'text-sky-400 animate-pulse';
+			case 'failed': return 'text-(--color-danger)';
+			case 'cancelled': return 'text-(--color-muted)';
+			default: return 'text-(--color-text)';
+		}
+	}
+
+	function fmtDate(s: string) {
+		if (!s) return '—';
+		return new Date(s).toLocaleString(undefined, {
+			month: 'short', day: 'numeric',
+			hour: '2-digit', minute: '2-digit'
+		});
+	}
+
+	function progress(job: AIJob) {
+		if (!job.items_total) return '';
+		const pct = Math.round((job.items_done / job.items_total) * 100);
+		return `${job.items_done}/${job.items_total} (${pct}%)`;
+	}
+
+	function feedURL(job: AIJob) {
+		const origin = page.url.origin;
+		return `${origin}/podcast/${job.slug}.xml?voice=${encodeURIComponent(job.model)}`;
+	}
+
+	async function copyFeedURL(job: AIJob) {
+		await navigator.clipboard.writeText(feedURL(job)).catch(() => {});
+	}
+
+	// ── Job submission ────────────────────────────────────────────────────────────
+	async function startJob() {
+		if (busy || !selectedSlug) return;
+		error = '';
+		successMsg = '';
+		busy = true;
+
+		const body: Record<string, unknown> = {
+			slug: selectedSlug,
+			voice: selectedVoice || undefined
+		};
+		if (fromChapter > 0) body.from_chapter = fromChapter;
+		if (toChapter > 0) body.to_chapter = toChapter;
+
+		try {
+			const res = await fetch('/api/admin/podcast', {
+				method: 'POST',
+				headers: { 'Content-Type': 'application/json' },
+				body: JSON.stringify(body)
+			});
+			const json = await res.json().catch(() => ({}));
+			if (!res.ok) {
+				error = json.error ?? `HTTP ${res.status}`;
+				return;
+			}
+			successMsg = `Job ${json.job_id} started — generating audio for chapters ${json.from}–${json.to}`;
+			// Optimistically prepend new job placeholder.
+			jobs = [
+				{
+					id: json.job_id,
+					kind: 'podcast',
+					slug: selectedSlug,
+					status: 'running',
+					model: json.voice,
+					items_done: 0,
+					items_total: json.items_total,
+					from_item: json.from,
+					to_item: json.to,
+					started: new Date().toISOString(),
+					finished: '',
+					heartbeat_at: '',
+					error_message: '',
+					payload: ''
+				} as AIJob,
+				...jobs
+			];
+		} catch (e) {
+			error = String(e);
+		} finally {
+			busy = false;
+		}
+	}
+
+	async function cancelJob(id: string) {
+		await fetch(`/api/admin/ai-jobs/${id}/cancel`, { method: 'POST' }).catch(() => {});
+		jobs = jobs.map((j) => (j.id === id ? { ...j, status: 'cancelled' as const } : j));
+	}
+</script>
+
+<svelte:head>
+	<title>Podcast — Admin</title>
+</svelte:head>
+
+<div class="max-w-3xl">
+	<h1 class="text-xl font-bold text-(--color-text) mb-1">Podcast Feed</h1>
+	<p class="text-sm text-(--color-muted) mb-6">
+		Generate TTS audio for a book and publish it as a podcast RSS feed that any podcast app can subscribe to.
+	</p>
+
+	<!-- ── Generation form ─────────────────────────────────────────────────── -->
+	<div class="bg-(--color-surface-2) border border-(--color-border) rounded-xl p-5 mb-8 space-y-4">
+		<h2 class="text-sm font-semibold text-(--color-text)">Generate audiobook</h2>
+
+		<div class="grid grid-cols-1 sm:grid-cols-2 gap-3">
+			<!-- Book -->
+			<div>
+				<label class="block text-xs text-(--color-muted) mb-1" for="podcast-book">Book</label>
+				<select
+					id="podcast-book"
+					bind:value={selectedSlug}
+					class="w-full bg-(--color-surface) border border-(--color-border) rounded-lg px-3 py-2 text-sm text-(--color-text) focus:outline-none focus:border-(--color-brand)"
+				>
+					<option value="">— select a book —</option>
+					{#each data.books as book}
+						<option value={book.slug}>{book.title}</option>
+					{/each}
+				</select>
+			</div>
+
+			<!-- Voice -->
+			<div>
+				<label class="block text-xs text-(--color-muted) mb-1" for="podcast-voice">Voice</label>
+				<select
+					id="podcast-voice"
+					bind:value={selectedVoice}
+					class="w-full bg-(--color-surface) border border-(--color-border) rounded-lg px-3 py-2 text-sm text-(--color-text) focus:outline-none focus:border-(--color-brand)"
+				>
+					<option value="">— default —</option>
+					{#each data.voices as v}
+						<option value={v.id}>{v.id} ({v.engine} · {v.lang} · {v.gender})</option>
+					{/each}
+				</select>
+			</div>
+
+			<!-- From chapter -->
+			<div>
+				<label class="block text-xs text-(--color-muted) mb-1" for="podcast-from">From chapter</label>
+				<input
+					id="podcast-from"
+					type="number"
+					min="0"
+					bind:value={fromChapter}
+					placeholder="1 (default)"
+					class="w-full bg-(--color-surface) border border-(--color-border) rounded-lg px-3 py-2 text-sm text-(--color-text) focus:outline-none focus:border-(--color-brand)"
+				/>
+			</div>
+
+			<!-- To chapter -->
+			<div>
+				<label class="block text-xs text-(--color-muted) mb-1" for="podcast-to">To chapter</label>
+				<input
+					id="podcast-to"
+					type="number"
+					min="0"
+					bind:value={toChapter}
+					placeholder="all (default)"
+					class="w-full bg-(--color-surface) border border-(--color-border) rounded-lg px-3 py-2 text-sm text-(--color-text) focus:outline-none focus:border-(--color-brand)"
+				/>
+			</div>
+		</div>
+
+		{#if error}
+			<p class="text-sm text-(--color-danger)">{error}</p>
+		{/if}
+		{#if successMsg}
+			<p class="text-sm text-green-400">{successMsg}</p>
+		{/if}
+
+		<button
+			type="button"
+			disabled={busy || !selectedSlug}
+			onclick={startJob}
+			class="px-4 py-2 rounded-lg text-sm font-medium bg-(--color-brand) text-(--color-surface) hover:opacity-90 transition-opacity disabled:opacity-40 disabled:cursor-not-allowed flex items-center gap-2"
+		>
+			{#if busy}
+				<svg class="w-4 h-4 animate-spin" fill="none" viewBox="0 0 24 24">
+					<circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"/>
+					<path class="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4z"/>
+				</svg>
+			{/if}
+			Generate podcast
+		</button>
+	</div>
+
+	<!-- ── Job history ──────────────────────────────────────────────────────── -->
+	<h2 class="text-sm font-semibold text-(--color-text) mb-3">Job history</h2>
+
+	{#if jobs.length === 0}
+		<p class="text-sm text-(--color-muted)">No podcast jobs yet.</p>
+	{:else}
+		<div class="space-y-3">
+			{#each jobs as job (job.id)}
+				<div class="bg-(--color-surface-2) border border-(--color-border) rounded-xl p-4 flex flex-col gap-2">
+					<div class="flex items-start justify-between gap-2 flex-wrap">
+						<div>
+							<span class="text-sm font-medium text-(--color-text)">{job.slug}</span>
+							<span class="text-xs text-(--color-muted) ml-2">voice: {job.model}</span>
+						</div>
+						<span class="text-xs font-semibold {statusColor(job.status)}">{job.status}</span>
+					</div>
+
+					<!-- Progress bar -->
+					{#if job.items_total > 0}
+						<div class="w-full bg-(--color-surface) rounded-full h-1.5">
+							<div
+								class="bg-(--color-brand) h-1.5 rounded-full transition-all"
+								style="width: {Math.round((job.items_done / job.items_total) * 100)}%"
+							></div>
+						</div>
+						<p class="text-xs text-(--color-muted)">{progress(job)}</p>
+					{/if}
+
+					{#if job.error_message}
+						<p class="text-xs text-(--color-danger)">{job.error_message}</p>
+					{/if}
+
+					<div class="flex items-center gap-2 flex-wrap text-xs text-(--color-muted)">
+						<span>Started: {fmtDate(job.started ?? '')}</span>
+						{#if job.finished}
+							<span>·</span>
+							<span>Finished: {fmtDate(job.finished)}</span>
+						{/if}
+					</div>
+
+					<div class="flex gap-2 flex-wrap mt-1">
+						<!-- Feed URL (only useful once job is done/in-progress) -->
+						<button
+							type="button"
+							onclick={() => copyFeedURL(job)}
+							class="text-xs px-2.5 py-1 rounded-lg bg-(--color-surface) border border-(--color-border) text-(--color-muted) hover:text-(--color-text) transition-colors flex items-center gap-1.5"
+						>
+							<svg class="w-3.5 h-3.5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+								<path stroke-linecap="round" stroke-linejoin="round" stroke-width="2"
+									d="M8 5H6a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2v-1M8 5a2 2 0 002 2h2a2 2 0 002-2M8 5a2 2 0 012-2h2a2 2 0 012 2m0 0h2a2 2 0 012 2v3m2 4H10m0 0l3-3m-3 3l3 3" />
+							</svg>
+							Copy feed URL
+						</button>
+
+						<!-- Cancel button for running/pending jobs -->
+						{#if job.status === 'running' || job.status === 'pending'}
+							<button
+								type="button"
+								onclick={() => cancelJob(job.id)}
+								class="text-xs px-2.5 py-1 rounded-lg bg-red-500/10 text-red-400 border border-red-500/30 hover:bg-red-500/20 transition-colors"
+							>
+								Cancel
+							</button>
+						{/if}
+					</div>
+				</div>
+			{/each}
+		</div>
+	{/if}
+
+	<!-- ── How to subscribe ─────────────────────────────────────────────────── -->
+	<div class="mt-8 bg-(--color-surface-2) border border-(--color-border) rounded-xl p-5">
+		<h2 class="text-sm font-semibold text-(--color-text) mb-2">How to subscribe</h2>
+		<ol class="text-sm text-(--color-muted) list-decimal list-inside space-y-1">
+			<li>Click <strong class="text-(--color-text)">Generate podcast</strong> above to create audio for your book.</li>
+			<li>Once running, copy the feed URL with the button above.</li>
+			<li>Open your podcast app (Apple Podcasts, Spotify, Pocket Casts, etc.).</li>
+			<li>Add the feed URL as a custom RSS feed / podcast URL.</li>
+			<li>As more chapters are generated they will appear automatically on the next feed refresh.</li>
+		</ol>
+		<p class="text-xs text-(--color-muted) mt-3">
+			Feed URL format: <code class="bg-(--color-surface) px-1 py-0.5 rounded text-xs">/podcast/&lt;slug&gt;.xml?voice=&lt;voice-id&gt;</code>
+		</p>
+	</div>
+</div>

ui/src/routes/api/admin/podcast/+server.ts

@@ -0,0 +1,34 @@
+/**
+ * POST /api/admin/podcast
+ *
+ * Admin-only proxy to the Go backend's podcast generation endpoint.
+ * Body: { slug, voice?, from_chapter?, to_chapter? }
+ * Response 202: { job_id, slug, voice, from, to, items_total }
+ */
+
+import { json, error } from '@sveltejs/kit';
+import type { RequestHandler } from './$types';
+import { log } from '$lib/server/logger';
+import { backendFetch } from '$lib/server/scraper';
+
+export const POST: RequestHandler = async ({ request, locals }) => {
+	if (!locals.user || locals.user.role !== 'admin') {
+		throw error(403, 'Forbidden');
+	}
+
+	const body = await request.text();
+	let res: Response;
+	try {
+		res = await backendFetch('/api/admin/podcast', {
+			method: 'POST',
+			headers: { 'content-type': 'application/json' },
+			body
+		});
+	} catch (e) {
+		log.error('admin/podcast', 'backend proxy error', { err: String(e) });
+		throw error(502, 'Could not reach backend');
+	}
+
+	const data = await res.json().catch(() => ({}));
+	return json(data, { status: res.status });
+};