Initial commit: MVP scaffolding for Line of Sight application

- React frontend with MapLibre integration
- Node.js Express backend with dummy API
- Docker containerization (PostgreSQL+PostGIS, backend, frontend)
- Interactive map with direction selector
- 20 mock conurbations data
- Full project structure ready for PR workflow

frontend/package.json

@@ -0,0 +1,22 @@
+{
+  "name": "line-of-sight-frontend",
+  "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"
+  },
+  "scripts": {
+    "start": "react-scripts start",
+    "build": "react-scripts build",
+    "test": "react-scripts test",
+    "eject": "react-scripts eject"
+  },
+  "browserslist": {
+    "production": [">0.2%", "not dead", "not op_mini all"],
+    "development": ["last 1 chrome version", "last 1 firefox version", "last 1 safari version"]
+  }
+}