Switch path alias from @ to ~, add Prettier with organize-imports

frontend/package.json

@@ -12,7 +12,9 @@
     "dev": "vite",
     "build": "tsc -b && vite build",
     "preview": "vite preview",
-    "typecheck": "tsc -b --noEmit"
+    "typecheck": "tsc -b --noEmit",
+    "format": "prettier --ignore-unknown --write .",
+    "format:check": "prettier --check ."
   },
   "dependencies": {
     "@radix-ui/react-dropdown-menu": "2.1.16",
@@ -40,6 +42,8 @@
     "@types/react": "18.3.28",
     "@types/react-dom": "18.3.7",
     "@vitejs/plugin-react": "4.7.0",
+    "prettier": "3.8.3",
+    "prettier-plugin-organize-imports": "4.3.0",
     "tailwindcss": "4.1.16",
     "typescript": "5.9.3",
     "vite": "6.4.2"