Modernize stack (React 19, Vite, Node 24) and add map preview features

frontend/package.json

@@ -3,20 +3,35 @@
   "version": "1.0.0",
   "private": true,
   "dependencies": {
-    "react": "^18.2.0",
-    "react-dom": "^18.2.0",
-    "react-scripts": "5.0.1",
-    "maplibre-gl": "^3.6.2",
-    "axios": "^1.6.2"
+    "axios": "^1.7.9",
+    "maplibre-gl": "^5.20.1",
+    "react": "^19.2.1",
+    "react-dom": "^19.2.1"
+  },
+  "devDependencies": {
+    "@testing-library/jest-dom": "^6.6.0",
+    "@testing-library/react": "^16.1.0",
+    "@vitejs/plugin-react": "^4.3.0",
+    "jsdom": "^29.0.0",
+    "vite": "^6.0.0",
+    "vitest": "^3.0.0"
   },
   "scripts": {
-    "start": "react-scripts start",
-    "build": "react-scripts build",
-    "test": "react-scripts test",
-    "eject": "react-scripts eject"
+    "start": "vite",
+    "build": "vite build",
+    "preview": "vite preview",
+    "test": "vitest"
   },
   "browserslist": {
-    "production": [">0.2%", "not dead", "not op_mini all"],
-    "development": ["last 1 chrome version", "last 1 firefox version", "last 1 safari version"]
+    "production": [
+      ">0.2%",
+      "not dead",
+      "not op_mini all"
+    ],
+    "development": [
+      "last 1 chrome version",
+      "last 1 firefox version",
+      "last 1 safari version"
+    ]
   }
 }