Migrate geo backend from Django/Graphene to Express + Apollo Server + arangojs

Replace Python stack with TypeScript. All 30+ GraphQL queries preserved including
phase-based routing (Dijkstra), H3 clustering, K_SHORTEST_PATHS, and external
routing services (GraphHopper, OpenRailRouting). Single public endpoint, no auth.

tsconfig.json

@@ -0,0 +1,19 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "outDir": "dist",
+    "rootDir": "src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true
+  },
+  "include": ["src"],
+  "exclude": ["node_modules", "dist"]
+}