feat(frontend): rework home page with recent, latest and playlists

Add SSR data loading for the home page and rebuild its layout (greeting hero, recently played, new releases, user playlists).

frontend/src/routes/+page.server.ts

@@ -0,0 +1,33 @@
+import type { PageServerLoad } from './$types';
+import { createApiClient } from '$lib/server/api';
+
+export const load: PageServerLoad = async ({ locals, fetch }) => {
+	const api = createApiClient({ fetch, accessToken: locals.accessToken ?? undefined });
+
+	const latestPromise = api.GET('/tracks', {
+		params: { query: { pageNumber: 1, pageSize: 12 } }
+	});
+	const playlistsPromise = locals.user
+		? api.GET('/playlists/users/{userId}', {
+				params: { path: { userId: locals.user.sub }, query: { pageNumber: 1, pageSize: 8 } }
+			})
+		: Promise.resolve({ data: undefined });
+
+	const [latest, playlists] = await Promise.all([latestPromise, playlistsPromise]);
+	const playlistItems = playlists.data?.items ?? [];
+
+	const covers = await Promise.all(
+		playlistItems.map(async (playlist) => {
+			const { data: tracks } = await api.GET('/playlists/{playlistId}/tracks', {
+				params: { path: { playlistId: playlist.id }, query: { pageNumber: 1, pageSize: 4 } }
+			});
+			return [playlist.id, tracks?.items.map((t) => t.id) ?? []] as const;
+		})
+	);
+
+	return {
+		latest: latest.data?.items ?? [],
+		playlists: playlistItems,
+		trackIds: Object.fromEntries(covers) as Record<string, string[]>
+	};
+};