feat(youtube): add YouTube browser window and Whisper subtitle source

- Add `subminer youtube`/`yt` and tray "Browse YouTube" window that plays or queues picked videos in mpv
- Add `youtube.subtitleSource` (`youtube` | `whisper`) to transcribe YouTube audio via subtitle generation
- Allow the subtitle generation modal on YouTube videos
- Pick the real Japanese track over machine-translated ones and fall back to yt-dlp on HTTP 429
- Remove legacy launcher youtubeSubgen/whisper/AI args and `--youtube-mode`
- Fix EPIPE crash when the launching terminal is closed with Ctrl+C
- Thin media timing review handles with orange original-boundary bars
- Update docs and change fragments

src/types/config.ts

@@ -20,7 +20,7 @@ import type {
   YomitanConfig,
   YoutubeConfig,
   YoutubeMediaCacheMode,
-  YoutubeSubgenConfig,
+  YoutubeSubtitleSource,
 } from './integrations';
 import type {
   ControllerButtonIndicesConfig,
@@ -174,7 +174,6 @@ export interface Config {
   discordPresence?: DiscordPresenceConfig;
   ai?: AiConfig;
   youtube?: YoutubeConfig;
-  youtubeSubgen?: YoutubeSubgenConfig;
   immersionTracking?: ImmersionTrackingConfig;
   stats?: StatsConfig;
   updates?: UpdatesConfig;
@@ -394,19 +393,12 @@ export interface ResolvedConfig {
   };
   youtube: YoutubeConfig & {
     primarySubLanguages: string[];
+    subtitleSource: YoutubeSubtitleSource;
     mediaCache: {
       mode: YoutubeMediaCacheMode;
       maxHeight: number;
     };
   };
-  youtubeSubgen: YoutubeSubgenConfig & {
-    whisperBin: string;
-    whisperModel: string;
-    whisperVadModel: string;
-    whisperThreads: number;
-    fixWithAi: boolean;
-    ai: AiFeatureConfig;
-  };
   immersionTracking: {
     enabled: boolean;
     dbPath?: string;

src/types/integrations.ts

@@ -124,6 +124,9 @@ export interface AiConfig {
 
 export type YoutubeMediaCacheMode = 'direct' | 'background';
 
+/** Where primary YouTube subtitles come from: YouTube's captions, or Whisper on the audio. */
+export type YoutubeSubtitleSource = 'youtube' | 'whisper';
+
 export interface YoutubeMediaCacheConfig {
   mode?: YoutubeMediaCacheMode;
   maxHeight?: number;
@@ -131,18 +134,10 @@ export interface YoutubeMediaCacheConfig {
 
 export interface YoutubeConfig {
   primarySubLanguages?: string[];
+  subtitleSource?: YoutubeSubtitleSource;
   mediaCache?: YoutubeMediaCacheConfig;
 }
 
-export interface YoutubeSubgenConfig {
-  whisperBin?: string;
-  whisperModel?: string;
-  whisperVadModel?: string;
-  whisperThreads?: number;
-  fixWithAi?: boolean;
-  ai?: AiFeatureConfig;
-}
-
 export interface StatsConfig {
   toggleKey?: string;
   markWatchedKey?: string;