feat: add chapter announcing setting to audio player

When enabled, the Web Speech API speaks the upcoming chapter number and
title (e.g. 'Chapter 12 — The Final Battle') between auto-next chapters,
giving an audible cue before the next narration begins.

- AudioStore.announceChapter ( boolean, default false)
- PBUserSettings.announce_chapter persisted to PocketBase
- GET/PUT /api/settings includes announceChapter field
- +layout.server.ts loads + defaults the field
- +layout.svelte applies on load, saves in debounced PUT, and fires
  SpeechSynthesisUtterance in onended before navigating (falls back to
  immediate navigation if speechSynthesis is unavailable)
- ListeningMode: 'Announce' pill added to the Speed · Auto · Sleep row

ui/src/lib/audio.svelte.ts

@@ -101,6 +101,13 @@ class AudioStore {
 	 */
 	autoNext = $state(false);
 
+	/**
+	 * When true, announces the upcoming chapter number and title via the
+	 * Web Speech API before auto-next navigation fires.
+	 * e.g. "Chapter 12 — The Final Battle"
+	 */
+	announceChapter = $state(false);
+
 	/**
 	 * The next chapter number for the currently playing chapter, or null if
 	 * there is no next chapter.  Written by the chapter page's AudioPlayer.

ui/src/lib/components/ListeningMode.svelte

@@ -618,8 +618,8 @@
 			{/if}
 		</div>
 
-		<!-- Secondary controls: unified single row — Speed · Auto · Sleep -->
+		<!-- Secondary controls: unified single row — Speed · Auto · Announce · Sleep -->
-		<div class="flex items-center justify-center gap-2 shrink-0">
+		<div class="flex items-center justify-center gap-2 shrink-0 flex-wrap">
 			<!-- Speed — segmented pill -->
 			<div class="flex items-center gap-0.5 bg-(--color-surface-2) rounded-full px-1.5 py-1 border border-(--color-border)">
 				{#each SPEED_OPTIONS as s}
@@ -661,6 +661,25 @@
 				{/if}
 			</button>
 
+			<!-- Announce chapter pill (only meaningful when auto-next is on) -->
+			<button
+				type="button"
+				onclick={() => (audioStore.announceChapter = !audioStore.announceChapter)}
+				class={cn(
+					'flex items-center gap-1.5 px-3 py-1.5 rounded-full text-xs font-semibold border transition-colors',
+					audioStore.announceChapter
+						? 'border-(--color-brand) bg-(--color-brand)/15 text-(--color-brand)'
+						: 'border-(--color-border) bg-(--color-surface-2) text-(--color-muted) hover:text-(--color-text)'
+				)}
+				aria-pressed={audioStore.announceChapter}
+				title={audioStore.announceChapter ? 'Chapter announcing on' : 'Chapter announcing off'}
+			>
+				<svg class="w-3.5 h-3.5" fill="currentColor" viewBox="0 0 24 24">
+					<path d="M3 9v6h4l5 5V4L7 9H3zm13.5 3c0-1.77-1.02-3.29-2.5-4.03v8.05c1.48-.73 2.5-2.25 2.5-4.02z"/>
+				</svg>
+				Announce
+			</button>
+
 			<!-- Sleep timer pill -->
 			<button
 				type="button"

ui/src/lib/server/pocketbase.ts

@@ -75,6 +75,7 @@ export interface PBUserSettings {
 	locale?: string;
 	font_family?: string;
 	font_size?: number;
+	announce_chapter?: boolean;
 	updated?: string;
 }
 
@@ -998,7 +999,7 @@ export async function getSettings(
 
 export async function saveSettings(
 	sessionId: string,
-	settings: { autoNext: boolean; voice: string; speed: number; theme?: string; locale?: string; fontFamily?: string; fontSize?: number },
+	settings: { autoNext: boolean; voice: string; speed: number; theme?: string; locale?: string; fontFamily?: string; fontSize?: number; announceChapter?: boolean },
 	userId?: string
 ): Promise<void> {
 	const existing = await listOne<PBUserSettings & { id: string }>(
@@ -1017,6 +1018,7 @@ export async function saveSettings(
 	if (settings.locale !== undefined) payload.locale = settings.locale;
 	if (settings.fontFamily !== undefined) payload.font_family = settings.fontFamily;
 	if (settings.fontSize !== undefined) payload.font_size = settings.fontSize;
+	if (settings.announceChapter !== undefined) payload.announce_chapter = settings.announceChapter;
 	if (userId) payload.user_id = userId;
 
 	if (existing) {

ui/src/routes/+layout.server.ts

@@ -17,7 +17,7 @@ export const load: LayoutServerLoad = async ({ locals, url, cookies }) => {
 		redirect(302, `/login`);
 	}
 
-	let settings = { autoNext: false, voice: 'af_bella', speed: 1.0, theme: 'amber', locale: 'en', fontFamily: 'system', fontSize: 1.0 };
+	let settings = { autoNext: false, voice: 'af_bella', speed: 1.0, theme: 'amber', locale: 'en', fontFamily: 'system', fontSize: 1.0, announceChapter: false };
 	try {
 		const row = await getSettings(locals.sessionId, locals.user?.id);
 		if (row) {
@@ -28,7 +28,8 @@ export const load: LayoutServerLoad = async ({ locals, url, cookies }) => {
 				theme: row.theme ?? 'amber',
 				locale: row.locale ?? 'en',
 				fontFamily: row.font_family ?? 'system',
-				fontSize: row.font_size || 1.0
+				fontSize: row.font_size || 1.0,
+				announceChapter: row.announce_chapter ?? false
 			};
 		}
 	} catch (e) {

ui/src/routes/+layout.svelte

@@ -107,6 +107,7 @@
 				audioStore.autoNext = data.settings.autoNext;
 				audioStore.voice = data.settings.voice;
 				audioStore.speed = data.settings.speed;
+				audioStore.announceChapter = data.settings.announceChapter ?? false;
 			}
 			// Always sync theme + font (profile page calls invalidateAll after saving)
 			currentTheme = data.settings.theme ?? 'amber';
@@ -128,6 +129,7 @@
 		const theme = currentTheme;
 		const fontFamily = currentFontFamily;
 		const fontSize = currentFontSize;
+		const announceChapter = audioStore.announceChapter;
 
 		// Skip saving until settings have been applied from the server AND
 		// at least one user-driven change has occurred after that.
@@ -138,7 +140,7 @@
 			fetch('/api/settings', {
 				method: 'PUT',
 				headers: { 'Content-Type': 'application/json' },
-				body: JSON.stringify({ autoNext, voice, speed, theme, fontFamily, fontSize })
+				body: JSON.stringify({ autoNext, voice, speed, theme, fontFamily, fontSize, announceChapter })
 			}).catch(() => {});
 		}, 800) as unknown as number;
 	});
@@ -377,9 +379,26 @@
 			// Store the target chapter number so only the newly-mounted AudioPlayer
 			// for that chapter reacts — not the outgoing chapter's component.
 			audioStore.autoStartChapter = targetChapter;
+
+			// Announce the upcoming chapter via Web Speech API if enabled.
+			const doNavigate = () => {
 				goto(`/books/${targetSlug}/chapters/${targetChapter}`).catch(() => {
 					audioStore.autoStartChapter = null;
 				});
+			};
+
+			if (audioStore.announceChapter && typeof window !== 'undefined' && 'speechSynthesis' in window) {
+				const nextInfo = audioStore.chapters.find((c) => c.number === targetChapter);
+				const titlePart = nextInfo?.title ? ` — ${nextInfo.title}` : '';
+				const text = `Chapter ${targetChapter}${titlePart}`;
+				window.speechSynthesis.cancel();
+				const utterance = new SpeechSynthesisUtterance(text);
+				utterance.onend = doNavigate;
+				utterance.onerror = doNavigate;
+				window.speechSynthesis.speak(utterance);
+			} else {
+				doNavigate();
+			}
 		}
 	}}
 	preload="metadata"

ui/src/routes/api/settings/+server.ts

@@ -5,7 +5,7 @@ import { log } from '$lib/server/logger';
 
 /**
  * GET /api/settings
- * Returns the current user's settings (auto_next, voice, speed, theme, locale, fontFamily, fontSize).
+ * Returns the current user's settings (auto_next, voice, speed, theme, locale, fontFamily, fontSize, announceChapter).
  * Returns defaults if no settings record exists yet.
  */
 export const GET: RequestHandler = async ({ locals }) => {
@@ -18,7 +18,8 @@ export const GET: RequestHandler = async ({ locals }) => {
 			theme: settings?.theme ?? 'amber',
 			locale: settings?.locale ?? 'en',
 			fontFamily: settings?.font_family ?? 'system',
-			fontSize: settings?.font_size || 1.0
+			fontSize: settings?.font_size || 1.0,
+			announceChapter: settings?.announce_chapter ?? false
 		});
 	} catch (e) {
 		log.error('settings', 'GET failed', { err: String(e) });
@@ -28,7 +29,7 @@ export const GET: RequestHandler = async ({ locals }) => {
 
 /**
  * PUT /api/settings
- * Body: { autoNext: boolean, voice: string, speed: number, theme?: string, locale?: string, fontFamily?: string, fontSize?: number }
+ * Body: { autoNext: boolean, voice: string, speed: number, theme?: string, locale?: string, fontFamily?: string, fontSize?: number, announceChapter?: boolean }
  * Saves user preferences.
  */
 export const PUT: RequestHandler = async ({ request, locals }) => {
@@ -67,6 +68,11 @@ export const PUT: RequestHandler = async ({ request, locals }) => {
 		error(400, `Invalid fontSize — must be one of: ${validFontSizes.join(', ')}`);
 	}
 
+	// announceChapter is optional boolean
+	if (body.announceChapter !== undefined && typeof body.announceChapter !== 'boolean') {
+		error(400, 'Invalid announceChapter — must be boolean');
+	}
+
 	try {
 		await saveSettings(locals.sessionId, body, locals.user?.id);
 	} catch (e) {