feat: db connection and migration

server/utils/db.ts

@@ -0,0 +1,13 @@
+import postgres from "postgres";
+
+let _sql: ReturnType<typeof postgres> | null = null;
+
+/** Lazily-created shared postgres.js connection pool. */
+export function getSql() {
+  if (!_sql) {
+    const url = process.env.DATABASE_URL;
+    if (!url) throw new Error("DATABASE_URL not set");
+    _sql = postgres(url, { max: 5, idle_timeout: 30 });
+  }
+  return _sql;
+}