test: suppress act() console.error warnings in frontend test setup

Prevents OOM crashes when running the full Jest suite — the act() warning
stack traces were generating 16k+ lines of output which exhausted Node heap.
All assertions still run; only the noisy console.error spam is silenced.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/tests/setup.js

@@ -1 +1,13 @@
 import '@testing-library/jest-dom';
+
+// Suppress noisy act() warnings from async state updates in useEffect hooks.
+// All assertions still run — this only silences the console.error spam that
+// causes OOM crashes when running the full suite.
+const originalError = console.error;
+beforeAll(() => {
+  console.error = (...args) => {
+    if (typeof args[0] === 'string' && args[0].includes('not wrapped in act')) return;
+    originalError(...args);
+  };
+});
+afterAll(() => { console.error = originalError; });