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/lib/ipc-client.ts

@@ -0,0 +1,96 @@
+import type {
+  OverviewData, DailyRollup, MonthlyRollup,
+  SessionSummary, SessionTimelinePoint, SessionEvent,
+  VocabularyEntry, KanjiEntry,
+  VocabularyOccurrenceEntry,
+  MediaLibraryItem, MediaDetailData,
+  AnimeLibraryItem, AnimeDetailData, AnimeWord,
+  StreakCalendarDay, EpisodesPerDay, NewAnimePerDay, WatchTimePerAnime,
+  WordDetailData, KanjiDetailData,
+  EpisodeDetailData,
+} from '../types/stats';
+
+interface StatsElectronAPI {
+  stats: {
+    getOverview: () => Promise<OverviewData>;
+    getDailyRollups: (limit?: number) => Promise<DailyRollup[]>;
+    getMonthlyRollups: (limit?: number) => Promise<MonthlyRollup[]>;
+    getSessions: (limit?: number) => Promise<SessionSummary[]>;
+    getSessionTimeline: (id: number, limit?: number) => Promise<SessionTimelinePoint[]>;
+    getSessionEvents: (id: number, limit?: number) => Promise<SessionEvent[]>;
+    getVocabulary: (limit?: number) => Promise<VocabularyEntry[]>;
+    getWordOccurrences: (
+      headword: string,
+      word: string,
+      reading: string,
+      limit?: number,
+      offset?: number,
+    ) => Promise<VocabularyOccurrenceEntry[]>;
+    getKanji: (limit?: number) => Promise<KanjiEntry[]>;
+    getKanjiOccurrences: (
+      kanji: string,
+      limit?: number,
+      offset?: number,
+    ) => Promise<VocabularyOccurrenceEntry[]>;
+    getMediaLibrary: () => Promise<MediaLibraryItem[]>;
+    getMediaDetail: (videoId: number) => Promise<MediaDetailData>;
+    getAnimeLibrary: () => Promise<AnimeLibraryItem[]>;
+    getAnimeDetail: (animeId: number) => Promise<AnimeDetailData>;
+    getAnimeWords: (animeId: number, limit?: number) => Promise<AnimeWord[]>;
+    getAnimeRollups: (animeId: number, limit?: number) => Promise<DailyRollup[]>;
+    getAnimeCoverUrl: (animeId: number) => string;
+    getStreakCalendar: (days?: number) => Promise<StreakCalendarDay[]>;
+    getEpisodesPerDay: (limit?: number) => Promise<EpisodesPerDay[]>;
+    getNewAnimePerDay: (limit?: number) => Promise<NewAnimePerDay[]>;
+    getWatchTimePerAnime: (limit?: number) => Promise<WatchTimePerAnime[]>;
+    getWordDetail: (wordId: number) => Promise<WordDetailData>;
+    getKanjiDetail: (kanjiId: number) => Promise<KanjiDetailData>;
+    getEpisodeDetail: (videoId: number) => Promise<EpisodeDetailData>;
+    ankiBrowse: (noteId: number) => Promise<void>;
+    ankiNotesInfo: (noteIds: number[]) => Promise<Array<{ noteId: number; fields: Record<string, { value: string }> }>>;
+    hideOverlay: () => void;
+  };
+}
+
+declare global {
+  interface Window {
+    electronAPI?: StatsElectronAPI;
+  }
+}
+
+function getIpc(): StatsElectronAPI['stats'] {
+  const api = window.electronAPI?.stats;
+  if (!api) throw new Error('Electron IPC not available');
+  return api;
+}
+
+export const ipcClient = {
+  getOverview: () => getIpc().getOverview(),
+  getDailyRollups: (limit = 60) => getIpc().getDailyRollups(limit),
+  getMonthlyRollups: (limit = 24) => getIpc().getMonthlyRollups(limit),
+  getSessions: (limit = 50) => getIpc().getSessions(limit),
+  getSessionTimeline: (id: number, limit = 200) => getIpc().getSessionTimeline(id, limit),
+  getSessionEvents: (id: number, limit = 500) => getIpc().getSessionEvents(id, limit),
+  getVocabulary: (limit = 100) => getIpc().getVocabulary(limit),
+  getWordOccurrences: (headword: string, word: string, reading: string, limit = 50, offset = 0) =>
+    getIpc().getWordOccurrences(headword, word, reading, limit, offset),
+  getKanji: (limit = 100) => getIpc().getKanji(limit),
+  getKanjiOccurrences: (kanji: string, limit = 50, offset = 0) =>
+    getIpc().getKanjiOccurrences(kanji, limit, offset),
+  getMediaLibrary: () => getIpc().getMediaLibrary(),
+  getMediaDetail: (videoId: number) => getIpc().getMediaDetail(videoId),
+  getAnimeLibrary: () => getIpc().getAnimeLibrary(),
+  getAnimeDetail: (animeId: number) => getIpc().getAnimeDetail(animeId),
+  getAnimeWords: (animeId: number, limit = 50) => getIpc().getAnimeWords(animeId, limit),
+  getAnimeRollups: (animeId: number, limit = 90) => getIpc().getAnimeRollups(animeId, limit),
+  getAnimeCoverUrl: (animeId: number) => getIpc().getAnimeCoverUrl(animeId),
+  getStreakCalendar: (days = 90) => getIpc().getStreakCalendar(days),
+  getEpisodesPerDay: (limit = 90) => getIpc().getEpisodesPerDay(limit),
+  getNewAnimePerDay: (limit = 90) => getIpc().getNewAnimePerDay(limit),
+  getWatchTimePerAnime: (limit = 90) => getIpc().getWatchTimePerAnime(limit),
+  getWordDetail: (wordId: number) => getIpc().getWordDetail(wordId),
+  getKanjiDetail: (kanjiId: number) => getIpc().getKanjiDetail(kanjiId),
+  getEpisodeDetail: (videoId: number) => getIpc().getEpisodeDetail(videoId),
+  ankiBrowse: (noteId: number) => getIpc().ankiBrowse(noteId),
+  ankiNotesInfo: (noteIds: number[]) => getIpc().ankiNotesInfo(noteIds),
+};