feat(backend): add foundation services and sql idempotency

backend/command-api/scripts/migrate-idempotency.mjs

@@ -0,0 +1,29 @@
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { Pool } from 'pg';
+
+const databaseUrl = process.env.IDEMPOTENCY_DATABASE_URL;
+
+if (!databaseUrl) {
+  // eslint-disable-next-line no-console
+  console.error('IDEMPOTENCY_DATABASE_URL is required');
+  process.exit(1);
+}
+
+const scriptDir = resolve(fileURLToPath(new URL('.', import.meta.url)));
+const migrationPath = resolve(scriptDir, '../sql/001_command_idempotency.sql');
+const sql = readFileSync(migrationPath, 'utf8');
+
+const pool = new Pool({
+  connectionString: databaseUrl,
+  max: Number.parseInt(process.env.IDEMPOTENCY_DB_POOL_MAX || '5', 10),
+});
+
+try {
+  await pool.query(sql);
+  // eslint-disable-next-line no-console
+  console.log('Idempotency migration applied successfully');
+} finally {
+  await pool.end();
+}