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>

test/buildArgs.test.ts

@@ -461,6 +461,60 @@ describe('sidecar files', () => {
   })
 })
 
+describe('format sorting (-S)', () => {
+  it('emits a raw -S string when formatSort is set, overriding the codec tiebreaker', () => {
+    const argv = build(opts(), dlo({ formatSort: 'res:1080,vcodec:av01', preferredVideoCodec: 'h264' }))
+    expect(hasSeq(argv, '-S', 'res:1080,vcodec:av01')).toBe(true)
+    expect(hasSeq(argv, '-S', 'res,fps,vcodec:h264')).toBe(false)
+  })
+
+  it('falls back to the codec tiebreaker when formatSort is empty', () => {
+    const argv = build(opts(), dlo({ formatSort: '', preferredVideoCodec: 'vp9' }))
+    expect(hasSeq(argv, '-S', 'res,fps,vcodec:vp9')).toBe(true)
+  })
+})
+
+describe('selectExtraArgs url-pattern matching', () => {
+  const base = {
+    customCommandEnabled: true,
+    perDownloadExtraArgs: undefined,
+    defaultTemplateId: null as string | null
+  }
+  const templates = [
+    { id: 'a', args: '--audio-quality 0', urlPattern: 'soundcloud\\.com' },
+    { id: 'b', args: '--write-thumbnail' }
+  ]
+
+  it('auto-applies a template whose urlPattern matches the URL', () => {
+    const out = selectExtraArgs({ ...base, templates, url: 'https://soundcloud.com/x/y' })
+    expect(out).toEqual(['--audio-quality', '0'])
+  })
+
+  it('does not apply a urlPattern template to a non-matching URL', () => {
+    const out = selectExtraArgs({ ...base, templates, url: 'https://youtube.com/watch?v=x' })
+    expect(out).toEqual([])
+  })
+
+  it('urlPattern match takes precedence over the global default template', () => {
+    const out = selectExtraArgs({
+      ...base,
+      defaultTemplateId: 'b',
+      templates,
+      url: 'https://soundcloud.com/x'
+    })
+    expect(out).toEqual(['--audio-quality', '0'])
+  })
+
+  it('a bad regex never matches (and is skipped safely)', () => {
+    const out = selectExtraArgs({
+      ...base,
+      templates: [{ id: 'c', args: '--x', urlPattern: '(' }],
+      url: 'https://soundcloud.com/x'
+    })
+    expect(out).toEqual([])
+  })
+})
+
 describe('chapters', () => {
   it('emits --split-chapters when splitChapters is on', () => {
     expect(build(opts(), dlo({ splitChapters: true }))).toContain('--split-chapters')