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/src-tauri/tauri.conf.json

@@ -0,0 +1,40 @@
+{
+  "$schema": "https://schema.tauri.app/config/2",
+  "productName": "Primora",
+  "version": "0.5.0",
+  "identifier": "dev.tdvorak.primora",
+  "build": {
+    "frontendDist": "../ui"
+  },
+  "app": {
+    "withGlobalTauri": true,
+    "windows": [
+      {
+        "label": "main",
+        "title": "Primora",
+        "width": 1280,
+        "height": 800,
+        "minWidth": 420,
+        "minHeight": 640,
+        "center": true
+      }
+    ],
+    "security": {
+      "csp": "default-src 'self'; connect-src 'self' ipc: http://ipc.localhost https: http:; img-src 'self' data:; style-src 'self'"
+    }
+  },
+  "bundle": {
+    "active": true,
+    "targets": "all",
+    "category": "DeveloperTool",
+    "shortDescription": "Primora desktop client",
+    "longDescription": "Thin desktop shell for a self-hosted Primora deployment. Renders the console served by your own server.",
+    "icon": [
+      "icons/32x32.png",
+      "icons/128x128.png",
+      "icons/[email protected]",
+      "icons/icon.icns",
+      "icons/icon.ico"
+    ]
+  }
+}