feat: Phase O Windows-native integration + settings search

- Taskbar progress bar: renderer pushes summarizeQueue aggregate over a new
  taskbar:progress channel (App store subscription); setProgressBar normal/error
- System tray (src/main/tray.ts) + minimize-to-tray (Settings.minimizeToTray);
  close hides to tray, isQuitting guards real exits; icon via getAppIconPath()
  (build/icon.ico added to extraResources)
- Jump list: app.setUserTasks "Open AeroFetch" (thumbnail toolbar deferred)
- Settings search: filters the ~11 SettingsView cards live by text match

Overlay badge deferred (needs a drawn NativeImage). typecheck + test (192) +
build all clean. Roadmap: Phase O COMPLETE.

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

src/shared/ipc.ts

@@ -76,7 +76,9 @@ export const IpcChannels = {
   terminalRun: 'terminal:run',
   terminalCancel: 'terminal:cancel',
   /** main → renderer push channel for live terminal output lines */
-  terminalOutput: 'terminal:output'
+  terminalOutput: 'terminal:output',
+  /** renderer → main: reflect overall queue progress on the Windows taskbar (Phase O) */
+  taskbarProgress: 'taskbar:progress'
 } as const
 
 /** Sentinel format id meaning "let yt-dlp pick the best video+audio". */
@@ -510,6 +512,8 @@ export interface Settings {
   autoDownloadNew: boolean
   /** false until the first-run welcome screen has been dismissed */
   hasCompletedOnboarding: boolean
+  /** keep AeroFetch running in the system tray when its window is closed (Phase O) */
+  minimizeToTray: boolean
 }
 
 /**
@@ -709,3 +713,11 @@ export interface TerminalRunResult {
   ok: boolean
   error?: string
 }
+
+/** Overall queue state for the Windows taskbar progress bar (Phase O). */
+export interface TaskbarProgress {
+  /** 0..1 overall fraction; ignored when mode is 'none' */
+  fraction: number
+  /** taskbar bar mode: hidden, normal, or red (some failed) */
+  mode: 'none' | 'normal' | 'error'
+}