fix(player): use untrack() in toggleRequest effect to prevent play/pause loop

Reading audioStore.isPlaying inside the toggleRequest $effect caused Svelte 5
to subscribe to it, so the effect re-ran on every isPlaying change. When
resuming from ListeningMode, play() would fire onplay → isPlaying=true →
effect re-ran → called pause() → onpause → isPlaying=false → effect re-ran
→ called play() → infinite loop. Wrapping the isPlaying read in untrack()
limits the effect's subscription to toggleRequest only.

ui/src/routes/+layout.svelte

@@ -2,7 +2,7 @@
 	import '../app.css';
 	import { page, navigating } from '$app/state';
 	import { goto } from '$app/navigation';
-	import { setContext } from 'svelte';
+	import { setContext, untrack } from 'svelte';
 	import type { Snippet } from 'svelte';
 	import type { LayoutData } from './$types';
 	import { audioStore } from '$lib/audio.svelte';
@@ -156,15 +156,23 @@
 	});
 
 	// Handle toggle requests from AudioPlayer controller.
+	// IMPORTANT: isPlaying must be read inside untrack() so the effect only
+	// re-runs when toggleRequest increments, not every time isPlaying changes.
+	// Without untrack the effect subscribes to both toggleRequest AND isPlaying,
+	// causing an infinite play/pause loop: play() fires onplay → isPlaying=true
+	// → effect re-runs → sees isPlaying=true → calls pause() → onpause fires
+	// → isPlaying=false → effect re-runs → calls play() → …
 	$effect(() => {
 		// Read toggleRequest to subscribe; ignore value 0 (initial).
 		const _req = audioStore.toggleRequest;
 		if (!audioEl || _req === 0) return;
-		if (audioStore.isPlaying) {
-			audioEl.pause();
-		} else {
-			audioEl.play().catch(() => {});
-		}
+		untrack(() => {
+			if (audioStore.isPlaying) {
+				audioEl!.pause();
+			} else {
+				audioEl!.play().catch(() => {});
+			}
+		});
 	});
 
 	// Handle seek requests from AudioPlayer controller.