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

backend/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "line-of-sight-backend",
+  "version": "1.0.0",
+  "description": "Line of Sight geospatial API backend",
+  "main": "app/server.js",
+  "scripts": {
+    "start": "node app/server.js",
+    "dev": "nodemon app/server.js",
+    "test": "jest"
+  },
+  "dependencies": {
+    "express": "^4.18.2",
+    "cors": "^2.8.5",
+    "pg": "^8.11.3",
+    "dotenv": "^16.3.1"
+  },
+  "devDependencies": {
+    "nodemon": "^3.0.1",
+    "jest": "^29.7.0"
+  }
+}