feat(stats): build anime-centric stats dashboard frontend

5-tab React dashboard with Catppuccin Mocha theme:
- Overview: hero stats, streak calendar, watch time chart, recent sessions
- Anime: grid with cover art, episode list with completion %, detail view
- Trends: 15 charts across Activity, Efficiency, Anime, and Patterns
- Vocabulary: POS-filtered word/kanji lists with detail panels
- Sessions: expandable session history with event timeline

Features:
- Cross-tab navigation (anime <-> vocabulary)
- Global word detail panel overlay
- Expandable episode detail with Anki card links (Expression field)
- Per-anime multi-line trend charts
- Watch time by day-of-week and hour-of-day
- Collapsible sections with accessibility (aria-expanded)
- Card size selector for anime grid
- Cover art caching via AniList
- HTTP API client with file:// protocol fallback for Electron overlay

stats/src/hooks/useAnimeDetail.ts

@@ -0,0 +1,22 @@
+import { useState, useEffect } from 'react';
+import { getStatsClient } from './useStatsApi';
+import type { AnimeDetailData } from '../types/stats';
+
+export function useAnimeDetail(animeId: number | null) {
+  const [data, setData] = useState<AnimeDetailData | null>(null);
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (animeId === null) return;
+    setLoading(true);
+    setError(null);
+    getStatsClient()
+      .getAnimeDetail(animeId)
+      .then(setData)
+      .catch((err: Error) => setError(err.message))
+      .finally(() => setLoading(false));
+  }, [animeId]);
+
+  return { data, loading, error };
+}