adds “save all state” utility

src/routes/+page.svelte

@@ -1,5 +1,11 @@
 <script lang="ts">
-	import { audio, episode_progress, user_preferences, type AudioLoadData } from '$lib';
+	import {
+		audio,
+		episode_progress,
+		save_podcast_state,
+		user_preferences,
+		type AudioLoadData,
+	} from '$lib';
 
 	const sources = {
 		syntax: {
@@ -24,6 +30,7 @@
 <a href="/another-page">Another Page</a>
 <button type="button" on:click={episode_progress.save_all}>Save progress</button>
 <button type="button" on:click={user_preferences.save}>Save preferences</button>
+<button type="button" on:click={save_podcast_state}>Save state (all)</button>
 
 <h5>Load Audio</h5>
 <button