feat: phase 5 distribution — tauri shell, pwa, desktop release artifacts

- apps/desktop: Tauri 2 thin shell; connect screen stores the deployment
  URL, webview renders the remote console, tray with Show/Change Server/
  Quit, close-to-tray, single-instance
- frontend: vite-plugin-pwa generates manifest + Workbox SW (shell
  precache, /api /auth /mailpit NetworkOnly), install banner on
  beforeinstallprompt, rasterized PWA icons
- release.yml: desktop bundle matrix (linux/macos/windows) attached to
  GitHub Releases
- workspace 0.5.0; Dockerfiles copy the desktop workspace manifest

Authored By: TDvorak <[email protected]>

apps/frontend/src/components/index.ts

@@ -13,6 +13,7 @@ export { Modal, ModalFooter } from "./Modal";
 export { NotificationCenter, addNotification, removeNotification, clearNotifications, notify } from "./NotificationCenter";
 export { OnboardingModal } from "./OnboardingModal";
 export { Progress, CircularProgress, Spinner } from "./Progress";
+export { PwaInstallBanner } from "./PwaInstallBanner";
 export { ProjectDashboard } from "./ProjectDashboard";
 export { Table, DataTable, Pagination } from "./Table";
 export { Tabs, TabPanel } from "./Tabs";