feat(home): add a "Recommended for you" shelf

Surface the content-based /me/recommendations feed as a horizontal shelf on
the homepage, below the Continue-reading shelf. Fetched after the catalogue
(same non-blocking pattern), shown only when signed in and the feed is
non-empty; reuses MangaCard in a fixed-width scroller. Component unit test +
e2e (signed-in shows cards, anonymous hides).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/lib/api/recommendations.ts

@@ -0,0 +1,17 @@
+import { ApiError, request } from './client';
+import type { MangaCard } from './mangas';
+
+/**
+ * GET /v1/me/recommendations — content-based "Recommended for you" feed.
+ * Returns an empty list for guests (401) so callers can render nothing
+ * without special-casing auth.
+ */
+export async function listMyRecommendations(): Promise<MangaCard[]> {
+    try {
+        const r = await request<{ items: MangaCard[] }>('/v1/me/recommendations');
+        return r.items;
+    } catch (e) {
+        if (e instanceof ApiError && e.status === 401) return [];
+        throw e;
+    }
+}