feat: Phase N power-user surface (terminal, palette, per-item, sort, url-templates)

- Built-in yt-dlp terminal: src/main/terminal.ts streams raw yt-dlp runs
  (binary fixed, gated on customCommandEnabled), new TerminalView + sidebar tab
- Command palette (Ctrl/Cmd+K), portal-free CommandPalette.tsx wired in App
- Per-playlist-item editing: per-row video/audio toggle + All video/All audio
  batch; addPlaylist enqueues via addMany with per-item kind
- Weighted format sorting: DownloadOptions.formatSort -> raw -S (overrides codec)
- URL-regex template auto-matching: CommandTemplate.urlPattern + selectExtraArgs
  matchesUrl, threaded through resolveExtraArgs; field in TemplateManager

typecheck + test (192) + electron-vite build all clean. Roadmap: Phase N COMPLETE.

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

src/main/download.ts

@@ -170,7 +170,8 @@ function resolveExtraArgs(opts: StartDownloadOptions, settings: Settings): strin
     customCommandEnabled: settings.customCommandEnabled,
     perDownloadExtraArgs: opts.extraArgs,
     defaultTemplateId: settings.defaultTemplateId,
-    templates: listTemplates()
+    templates: listTemplates(),
+    url: opts.url
   })
 }