feat: auto-updater integration

- Install electron-updater
- New updater.ts: check/download/install with progress events
- IPC: updater:check, updater:download, updater:install, updater:status
- Preload bridge for updater API
- electron-builder publish config (github provider)
- Fix build files path: out -> electron-dist
- i18n keys for updater notifications (zh-CN + en)

electron/preload/index.d.ts

@@ -105,6 +105,12 @@ export interface ElectronAPI {
     getCommandLog: () => Promise<any[]>
     clearCommandLog: () => Promise<void>
   }
+  updater: {
+    check: () => Promise<{ available: boolean; version?: string }>
+    download: () => Promise<{ success: boolean; error?: string }>
+    install: () => void
+    onStatus: (callback: (status: any) => void) => void
+  }
 }
 
 declare global {