feat: implement project export to Excel with API endpoint and UI button

package.json

@@ -9,6 +9,7 @@
     "start": "next start",
     "lint": "next lint",
     "create-admin": "node scripts/create-admin.js",
+    "export-projects": "node export-projects-to-excel.mjs",
     "test": "jest",
     "test:watch": "jest --watch",
     "test:coverage": "jest --coverage",
@@ -45,6 +46,7 @@
     "@testing-library/react": "^16.1.0",
     "@testing-library/user-event": "^14.5.0",
     "@types/leaflet": "^1.9.18",
+    "concurrently": "^9.2.1",
     "eslint": "^9",
     "eslint-config-next": "15.1.8",
     "jest": "^29.7.0",