Add Pinchflat-style media manager: index channels into playlist folders

Index an entire YouTube channel or playlist once, then download it into
organized <Channel>/<Playlist>/<NNN> - <Title> folders, with incremental
re-sync. Built in six rebuild-gated phases (F-K); see ROADMAP-PINCHFLAT.md.

- F: channel-walk indexer (/playlists + /videos) -> persisted Source +
  MediaItem JSON stores; pure classify/dedup logic in indexerCore.ts
- G: Windows-safe folder paths + dir sanitizer (collectionOutputTemplate)
- H: Library tab + source tree + "Download pending" into the existing queue
- I: state-preserving re-index merge + persist-downloaded-on-complete
- J: watched sources, RSS fast-check, Task Scheduler + --sync launch
  (the OS-level scheduling/RSS need a real-install smoke test)
- K: .info.json / thumbnail / .description sidecars for media servers

Also gitignore .gitea-token. 106 unit tests pass; typecheck + build clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/main/settings.ts

@@ -36,6 +36,7 @@ const DEFAULTS: Settings = {
   customCommandEnabled: false,
   defaultTemplateId: null,
   notifyOnComplete: true,
+  autoDownloadNew: true,
   hasCompletedOnboarding: false
 }
 
@@ -77,7 +78,10 @@ function sanitizeOptions(input: unknown): DownloadOptions {
     embedChapters: bool(o.embedChapters, d.embedChapters),
     embedMetadata: bool(o.embedMetadata, d.embedMetadata),
     embedThumbnail: bool(o.embedThumbnail, d.embedThumbnail),
-    cropThumbnail: bool(o.cropThumbnail, d.cropThumbnail)
+    cropThumbnail: bool(o.cropThumbnail, d.cropThumbnail),
+    writeInfoJson: bool(o.writeInfoJson, d.writeInfoJson),
+    writeThumbnailFile: bool(o.writeThumbnailFile, d.writeThumbnailFile),
+    writeDescription: bool(o.writeDescription, d.writeDescription)
   }
 }
 
@@ -163,6 +167,7 @@ export function setSettings(partial: Partial<Settings>): Settings {
       case 'downloadArchive':
       case 'customCommandEnabled':
       case 'notifyOnComplete':
+      case 'autoDownloadNew':
       case 'hasCompletedOnboarding':
         if (typeof value === 'boolean') s.set(key, value)
         break