feat: add Drizzle ORM database layer

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/db/index.js

@@ -0,0 +1,14 @@
+import { drizzle } from 'drizzle-orm/postgres-js';
+import postgres from 'postgres';
+import logger from '../utils/logger.js';
+import { files } from './schema.js';
+
+const client = postgres(process.env.DATABASE_URL, {
+  max: 10,
+  idle_timeout: 20,
+  connect_timeout: 10
+});
+
+export const db = drizzle(client, { schema: { files } });
+export { files };
+export default db;