feat: implement library.rs, types.ts, api.ts, and extract CSS

- library.rs: full video library management (1948 lines, 10 tests)
  folder scanning, progress tracking, playlists, subtitle integration,
  background duration scanning
- types.ts: all TypeScript interfaces for Tauri command responses
- api.ts: typed wrappers for all 26 Tauri invoke commands
- 6 CSS files extracted from Python HTML into src/styles/

src/api.ts

@@ -0,0 +1,92 @@
+import { invoke } from '@tauri-apps/api/core';
+import type {
+  LibraryInfo,
+  OkResponse,
+  PrefsResponse,
+  RecentsResponse,
+  NoteResponse,
+  VideoMetaResponse,
+  SubtitleResponse,
+  AvailableSubsResponse,
+  EmbeddedSubsResponse,
+} from './types';
+
+export const api = {
+  selectFolder: () =>
+    invoke<LibraryInfo>('select_folder'),
+
+  openFolderPath: (folder: string) =>
+    invoke<LibraryInfo>('open_folder_path', { folder }),
+
+  getRecents: () =>
+    invoke<RecentsResponse>('get_recents'),
+
+  removeRecent: (path: string) =>
+    invoke<OkResponse>('remove_recent', { path }),
+
+  getLibrary: () =>
+    invoke<LibraryInfo>('get_library'),
+
+  setCurrent: (index: number, timecode: number = 0) =>
+    invoke<OkResponse>('set_current', { index, timecode }),
+
+  tickProgress: (index: number, currentTime: number, duration: number | null, playing: boolean) =>
+    invoke<OkResponse>('tick_progress', { index, current_time: currentTime, duration, playing }),
+
+  setFolderVolume: (volume: number) =>
+    invoke<OkResponse>('set_folder_volume', { volume }),
+
+  setFolderAutoplay: (enabled: boolean) =>
+    invoke<OkResponse>('set_folder_autoplay', { enabled }),
+
+  setFolderRate: (rate: number) =>
+    invoke<OkResponse>('set_folder_rate', { rate }),
+
+  setOrder: (fids: string[]) =>
+    invoke<OkResponse>('set_order', { fids }),
+
+  startDurationScan: () =>
+    invoke<OkResponse>('start_duration_scan'),
+
+  getPrefs: () =>
+    invoke<PrefsResponse>('get_prefs'),
+
+  setPrefs: (patch: Record<string, unknown>) =>
+    invoke<OkResponse>('set_prefs', { patch }),
+
+  setAlwaysOnTop: (enabled: boolean) =>
+    invoke<OkResponse>('set_always_on_top', { enabled }),
+
+  saveWindowState: () =>
+    invoke<OkResponse>('save_window_state'),
+
+  getNote: (fid: string) =>
+    invoke<NoteResponse>('get_note', { fid }),
+
+  setNote: (fid: string, note: string) =>
+    invoke<OkResponse>('set_note', { fid, note }),
+
+  getCurrentVideoMeta: () =>
+    invoke<VideoMetaResponse>('get_current_video_meta'),
+
+  getCurrentSubtitle: () =>
+    invoke<SubtitleResponse>('get_current_subtitle'),
+
+  getEmbeddedSubtitles: () =>
+    invoke<EmbeddedSubsResponse>('get_embedded_subtitles'),
+
+  extractEmbeddedSubtitle: (trackIndex: number) =>
+    invoke<SubtitleResponse>('extract_embedded_subtitle', { track_index: trackIndex }),
+
+  getAvailableSubtitles: () =>
+    invoke<AvailableSubsResponse>('get_available_subtitles'),
+
+  loadSidecarSubtitle: (filePath: string) =>
+    invoke<SubtitleResponse>('load_sidecar_subtitle', { file_path: filePath }),
+
+  chooseSubtitleFile: () =>
+    invoke<SubtitleResponse>('choose_subtitle_file'),
+
+  resetWatchProgress: () =>
+    invoke<OkResponse>('reset_watch_progress'),
+};