feat(electron): add main process, preload, store, protocol, and type definitions

- Add ElectronAPI type definitions and runtime contract (isElectron guard)
- Add electron-store with backend connection data model
- Add centralized API base URL utility (api-base.ts)
- Implement app:// custom protocol with API proxy
- Implement preload script with full contextBridge API
- Complete main process: BrowserWindow config, IPC handlers, window controls
- Register app:// scheme as privileged for secure renderer access

dashboard/package.json

@@ -14,7 +14,56 @@
     "test:ui": "vitest --ui",
     "electron:dev": "electron-vite dev",
     "electron:build": "electron-vite build",
-    "electron:preview": "electron-vite preview"
+    "electron:preview": "electron-vite preview",
+    "electron:dist": "electron-vite build && electron-builder",
+    "electron:dist:mac": "electron-vite build && electron-builder --mac",
+    "electron:dist:win": "electron-vite build && electron-builder --win",
+    "electron:dist:linux": "electron-vite build && electron-builder --linux"
+  },
+  "build": {
+    "appId": "org.maibot.dashboard",
+    "productName": "MaiBot Dashboard",
+    "directories": {
+      "output": "dist-electron",
+      "buildResources": "electron/resources"
+    },
+    "files": [
+      "out/**/*",
+      "package.json"
+    ],
+    "mac": {
+      "category": "public.app-category.utilities",
+      "target": [
+        { "target": "dmg", "arch": ["x64", "arm64"] }
+      ],
+      "icon": "electron/resources/icon.icns",
+      "darkModeSupport": true
+    },
+    "win": {
+      "target": [
+        { "target": "nsis", "arch": ["x64"] }
+      ],
+      "icon": "electron/resources/icon.ico"
+    },
+    "linux": {
+      "target": [
+        { "target": "AppImage", "arch": ["x64"] }
+      ],
+      "icon": "electron/resources/icon.png",
+      "category": "Utility"
+    },
+    "nsis": {
+      "oneClick": false,
+      "allowToChangeInstallationDirectory": true,
+      "createDesktopShortcut": true,
+      "createStartMenuShortcut": true
+    },
+    "dmg": {
+      "contents": [
+        { "x": 130, "y": 220 },
+        { "x": 410, "y": 220, "type": "link", "path": "/Applications" }
+      ]
+    }
   },
   "dependencies": {
     "@codemirror/lang-css": "^6.3.1",
@@ -94,6 +143,7 @@
     "autoprefixer": "^10.4.22",
     "electron": "^40.6.1",
     "electron-builder": "^26.8.1",
+    "electron-store": "^8.1.0",
     "electron-vite": "^5.0.0",
     "eslint": "^9.39.1",
     "eslint-plugin-react-hooks": "^7.0.1",