refactor: rename frontend/ to web-player/ and format with prettier

Updates the compose build context, the Dockerfile header, the package
name and the docs. The compose service and container keep the name
frontend/musify-frontend, since nginx routes to http://frontend:3000.

The source files also carry the first prettier pass, so the rename and
the reformat land together for them.

web-player/src/routes/(app)/library/+page.server.ts

@@ -0,0 +1,38 @@
+import type { PageServerLoad, Actions } from './$types';
+import { fail } from '@sveltejs/kit';
+import {
+	createApiClient,
+	requireAccessTokenAction,
+	requireUser,
+	unwrapOrError,
+	unwrapOrFail
+} from '$lib/server/api';
+
+const PAGE_SIZE = 50;
+
+export const load: PageServerLoad = async ({ locals, url, fetch }) => {
+	const user = requireUser(locals, url);
+	const api = createApiClient({ fetch, accessToken: locals.accessToken ?? undefined });
+	const result = await api.GET('/tracks/users/{userId}', {
+		params: { path: { userId: user.sub }, query: { pageNumber: 1, pageSize: PAGE_SIZE } }
+	});
+
+	return { tracks: unwrapOrError(result, 'No se pudo cargar tu biblioteca.') };
+};
+
+export const actions: Actions = {
+	deleteTrack: async ({ request, locals, fetch }) => {
+		const accessToken = requireAccessTokenAction(locals);
+		if (typeof accessToken !== 'string') return accessToken;
+		const trackId = String((await request.formData()).get('trackId') ?? '');
+		if (!trackId) return fail(400, { message: 'Falta la canción.' });
+
+		const api = createApiClient({ fetch, accessToken });
+		const result = await api.DELETE('/tracks/{trackId}', {
+			params: { path: { trackId } }
+		});
+		const failure = unwrapOrFail(result, 'No se pudo borrar la canción.');
+		if (failure) return failure;
+		return { deleted: true };
+	}
+};