Refactor application structure and simplify implementation

package.json

@@ -6,7 +6,11 @@
   "description": "Standalone Windows desktop proxy management app for ProxyWarden.",
   "scripts": {
     "dev": "vite",
-    "build": "tsc && vite build",
+    "build": "npm run typecheck && vite build",
+    "typecheck": "tsc --noEmit",
+    "lint": "eslint src",
+    "format:check": "prettier --check \"src/**/*.{ts,tsx,css}\"",
+    "format": "prettier --write \"src/**/*.{ts,tsx,css}\"",
     "preview": "vite preview",
     "test": "vitest",
     "tauri": "tauri"
@@ -20,12 +24,16 @@
     "react-dom": "^19.0.0"
   },
   "devDependencies": {
+    "@eslint/js": "^10.0.1",
     "@tauri-apps/cli": "^2.0.0",
     "@types/react": "^19.0.0",
     "@types/react-dom": "^19.0.0",
     "@vitejs/plugin-react": "^5.0.0",
+    "eslint": "^10.7.0",
+    "prettier": "^3.9.5",
     "typescript": "^5.8.0",
-    "vitest": "^3.2.4",
-    "vite": "^7.0.0"
+    "typescript-eslint": "^8.63.0",
+    "vite": "^7.0.0",
+    "vitest": "^3.2.4"
   }
 }