feat: Electron desktop app — hardening, IPC bridge, and dev launch fixes

- Dev/prod URL auto-detection (Vite 5173 in dev, server 3000 in prod)
- Typed IPC bridge via preload (notifications, badge, window controls, updates, deep links)
- Native OS notifications via NotificationController with window focus suppression
- Auto-update via electron-updater with UpdateToast UI
- Deep linking (backspace:// protocol) for macOS and Windows/Linux
- Window state persistence (position, size, maximize across restarts)
- Tray icon with graceful fallback when icon asset missing
- Suppress PWA service worker polling/reloads inside Electron
- Platform detection layer (isElectron, getElectronAPI)
- Root workspace scripts (dev:desktop, build:desktop)
- Document BACKSPACE_URL and BACKSPACE_UPDATE_URL env vars

packages/desktop/electron-builder.yml

@@ -5,22 +5,30 @@ directories:
 files:
   - dist/**/*
   - "!node_modules"
+publish:
+  - provider: generic
+    url: "${BACKSPACE_UPDATE_URL}"
+    useMultipleRangeRequest: false
+protocols:
+  - name: Backspace
+    schemes:
+      - backspace
 mac:
   category: public.app-category.social-networking
   target:
     - dmg
     - zip
-  icon: build/icon.icns
+  # icon: build/icon.icns  # Uncomment when final icon is designed
 win:
   target:
     - nsis
-  icon: build/icon.ico
+  # icon: build/icon.ico  # Uncomment when final icon is designed
 linux:
   target:
     - AppImage
     - deb
   category: Network
-  icon: build/icons
+  # icon: build/icons  # Uncomment when final icons are designed
 nsis:
   oneClick: false
   allowToChangeInstallationDirectory: true