feat(backend): implement REST API for races calendar

Express + TypeScript backend with PostgreSQL: CRUD endpoints for /races (GET list with year/month filters, GET by id, POST, PATCH, DELETE), health/readiness probes, SQL migration runner, seed script with upsert from CSV, camelCase/snake_case mapper, CORS, env validation, docker-compose, and API docs for frontend.

Made-with: Cursor

backend/src/index.ts

@@ -0,0 +1,18 @@
+import express from "express";
+import cors from "cors";
+import { config } from "./config";
+import healthRouter from "./routes/health";
+import racesRouter from "./routes/races";
+
+const app = express();
+
+app.use(cors({ origin: config.corsOrigin, methods: ["GET", "POST", "PATCH", "DELETE"] }));
+app.use(express.json());
+
+app.use(healthRouter);
+app.use(racesRouter);
+
+app.listen(config.apiPort, () => {
+  console.log(`[api] Listening on http://localhost:${config.apiPort}`);
+  console.log(`[api] CORS origin: ${config.corsOrigin}`);
+});