fix(quick-260613-ndv): reset familysync_test each run (truncate-all)

CREATE DATABASE IF NOT EXISTS reuses the prior run's data, so the test DB
would itself accumulate users run-over-run (the same flaky list_shares
fan-out the dev DB suffered). Truncate every table (except the drizzle
migration ledger) at globalSetup start, FK-safe, so each run is a clean
deterministic slate. Verified: familysync_test users 186 -> 93 across a run
(reset, not doubled); dev familysync untouched at 3.

apps/api/test/global-setup.ts

@@ -105,9 +105,32 @@ export default async function setup(): Promise<void> {
       new URL('../src/db/migrations', import.meta.url),
     );
     await migrate(db, { migrationsFolder });
+
+    // Clean slate each run: truncate every table (except drizzle's migration
+    // ledger) so familysync_test does NOT accumulate rows across runs. Without
+    // this, CREATE DATABASE IF NOT EXISTS reuses the prior run's data and the
+    // users table grows unbounded — re-creating the slow/flaky list_shares
+    // fan-out the dev DB used to suffer, just in the test DB. FK-safe via the
+    // session FOREIGN_KEY_CHECKS toggle (scoped to this one connection).
+    const conn = await appPool.getConnection();
+    try {
+      const [rows] = await conn.query(
+        `SELECT table_name AS t FROM information_schema.tables
+         WHERE table_schema = ? AND table_type = 'BASE TABLE'
+           AND table_name <> '__drizzle_migrations'`,
+        [TEST_DB],
+      );
+      await conn.query('SET FOREIGN_KEY_CHECKS = 0');
+      for (const { t } of rows as Array<{ t: string }>) {
+        await conn.query(`TRUNCATE TABLE \`${t}\``);
+      }
+      await conn.query('SET FOREIGN_KEY_CHECKS = 1');
+    } finally {
+      conn.release();
+    }
   } finally {
     await appPool.end();
   }
 
-  console.log('[global-setup] provisioned + migrated familysync_test');
+  console.log('[global-setup] provisioned + migrated + reset familysync_test');
 }