feat(web-player): page the album results and save YouTube albums

The albums section keeps a Ver más button while YouTube Music has another
page, fed by a new /api/youtube/albums route that forwards the continuation
token. The YouTube album page gains a save button that drops the whole album,
tracks included, into your library and takes you to it.

web-player/src/routes/api/youtube/albums/+server.ts

@@ -0,0 +1,21 @@
+import type { RequestHandler } from './$types';
+import { json, error } from '@sveltejs/kit';
+import { createApiClient, requireAccessToken, unwrapOrError } from '$lib/server/api';
+
+export const GET: RequestHandler = async ({ url, locals, fetch }) => {
+	const accessToken = requireAccessToken(locals, 'Inicia sesión para buscar.');
+
+	const query = url.searchParams.get('query')?.trim() ?? '';
+	if (!query) {
+		error(400, 'Falta el término de búsqueda.');
+	}
+
+	const continuation = url.searchParams.get('continuation') ?? undefined;
+
+	const api = createApiClient({ fetch, accessToken });
+	const result = await api.GET('/youtube/albums', {
+		params: { query: { query, continuation } }
+	});
+
+	return json(unwrapOrError(result, 'No se pudieron buscar álbumes en YouTube Music.'));
+};