refactor: Prototype of tanstack-query (#34)

* move getApiUrl to api folder

* adjust imports

* tanstack-query example with homeData

* small adjustments

* fix key collision

* new MusicSource persistent mechanism example

* add error handling & set sveltekit to SPA mode

* remove unnecessary ssr test

frontend/src/lib/stores/musicSource.ts

@@ -7,14 +7,14 @@ export type MusicSource = 'listenbrainz' | 'lastfm';
 export type MusicSourcePage = keyof typeof PAGE_SOURCE_KEYS;
 
 const CACHED_SOURCE_KEY = 'musicseerr_primary_source';
-const DEFAULT_SOURCE: MusicSource = 'listenbrainz';
+export const DEFAULT_SOURCE: MusicSource = 'listenbrainz';
 
 interface MusicSourceState {
 	source: MusicSource;
 	loaded: boolean;
 }
 
-function isMusicSource(value: unknown): value is MusicSource {
+export function isMusicSource(value: unknown): value is MusicSource {
 	return value === 'listenbrainz' || value === 'lastfm';
 }
 

frontend/src/lib/stores/player.spec.ts

@@ -823,7 +823,6 @@ describe('beforeunload beacon', () => {
 	let addEventListenerSpy: ReturnType<typeof vi.fn>;
 	let removeEventListenerSpy: ReturnType<typeof vi.fn>;
 	let sendBeaconMock: ReturnType<typeof vi.fn>;
-	// eslint-disable-next-line @typescript-eslint/no-unused-vars
 	let jellyfinApi: {
 		startSession: ReturnType<typeof vi.fn>;
 		reportProgress: ReturnType<typeof vi.fn>;

frontend/src/lib/stores/syncStatus.svelte.ts

@@ -1,7 +1,7 @@
 import { browser } from '$app/environment';
 import { api } from '$lib/api/client';
 import { libraryStore } from '$lib/stores/library';
-import { getApiUrl } from '$lib/utils/api';
+import { getApiUrl } from '$lib/api/api-utils';
 
 export type SyncStatus = {
 	is_syncing: boolean;