Add test infrastructure for hydrators using node:test

- Add docker-compose.test.yml with isolated PostgreSQL on port 5433
- Add environment variable support for database connection config
- Add test setup utilities and initial user hydrator tests
- Add test and test:watch scripts to package.json

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

express/framework/hydrators/tests/setup.ts

@@ -0,0 +1,44 @@
+// Test setup for hydrator tests
+// Run: DB_PORT=5433 DB_USER=diachron_test DB_PASSWORD=diachron_test DB_NAME=diachron_test npx tsx --test tests/*.test.ts
+
+import { Pool } from "pg";
+import { connectionConfig, migrate } from "../../../database";
+
+const pool = new Pool(connectionConfig);
+
+export async function setupTestDatabase(): Promise<void> {
+    await migrate();
+}
+
+export async function cleanupTables(): Promise<void> {
+    // Clean in reverse dependency order
+    await pool.query("DELETE FROM user_emails");
+    await pool.query("DELETE FROM users");
+}
+
+export async function teardownTestDatabase(): Promise<void> {
+    await pool.end();
+}
+
+export async function insertTestUser(data: {
+    id: string;
+    displayName: string;
+    status: string;
+    email: string;
+}): Promise<void> {
+    const emailId = crypto.randomUUID();
+    const normalizedEmail = data.email.toLowerCase().trim();
+
+    await pool.query(
+        `INSERT INTO users (id, display_name, status) VALUES ($1, $2, $3)`,
+        [data.id, data.displayName, data.status],
+    );
+
+    await pool.query(
+        `INSERT INTO user_emails (id, user_id, email, normalized_email, is_primary)
+         VALUES ($1, $2, $3, $4, true)`,
+        [emailId, data.id, data.email, normalizedEmail],
+    );
+}
+
+export { pool };