feat: add Electron packaging with headless mode and --port support

- Add electron-builder for packaging
- Add --port argument support (default: 9997)
- Add electron/main.js as entry point
- Update package.json with build configuration
- Server runs headlessly without GUI window

package.json

@@ -4,17 +4,58 @@
   "description": "Web-based terminal using libghostty-vt and xterm.js",
   "main": "src/backend/server.js",
   "scripts": {
-    "start": "node src/backend/server.js",
-    "dev": "node src/backend/server.js",
-    "build:frontend": "echo 'Frontend is static, no build needed'"
+    "start": "electron .",
+    "dev": "electron . --port 9997",
+    "start:server": "node src/backend/server.js",
+    "build": "electron-builder",
+    "build:dir": "electron-builder --dir"
   },
-  "keywords": ["terminal", "web", "ghostty", "xterm"],
+  "keywords": [
+    "terminal",
+    "web",
+    "ghostty",
+    "xterm"
+  ],
   "license": "MIT",
+  "author": "XCTerminal",
   "dependencies": {
-    "ws": "^8.18.0",
-    "node-pty": "^1.0.0"
+    "node-pty": "^1.0.0",
+    "ws": "^8.18.0"
   },
   "devDependencies": {
+    "electron": "^41.0.3",
+    "electron-builder": "^26.8.1",
     "express": "^4.18.2"
+  },
+  "build": {
+    "appId": "com.xcterminal.app",
+    "productName": "XCTerminal",
+    "directories": {
+      "output": "dist"
+    },
+    "win": {
+      "target": [
+        {
+          "target": "portable",
+          "arch": ["x64"]
+        }
+      ]
+    },
+    "linux": {
+      "target": ["AppImage"]
+    },
+    "mac": {
+      "target": ["dmg"]
+    },
+    "files": [
+      "src/**/*",
+      "node_modules/**/*",
+      "!node_modules/.cache/**/*"
+    ],
+    "extraMetadata": {
+      "main": "src/backend/server.js"
+    },
+    "nodeGypRebuild": false,
+    "npmRebuild": false
   }
-}
+}