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/desktop/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "@primora/desktop",
+  "version": "0.5.0",
+  "private": true,
+  "description": "Primora desktop shell — thin Tauri client for a self-hosted deployment",
+  "scripts": {
+    "tauri": "tauri",
+    "dev": "tauri dev",
+    "bundle": "tauri build",
+    "check": "cargo check --manifest-path src-tauri/Cargo.toml"
+  },
+  "devDependencies": {
+    "@tauri-apps/cli": "^2.11.4"
+  }
+}