fix(quota): coalesce provider usage refreshes

packages/web/server/lib/quota/providers/index.test.js

@@ -1,7 +1,7 @@
 import { describe, expect, it } from 'vitest';
 
 import * as google from './google/index.js';
-import { listConfiguredQuotaProviders } from './index.js';
+import { fetchQuotaForProvider, listConfiguredQuotaProviders } from './index.js';
 
 describe('quota provider registry', () => {
   it('exposes google provider configuration helpers through the provider module', () => {
@@ -14,4 +14,13 @@ describe('quota provider registry', () => {
   it('can list configured providers without missing provider exports', () => {
     expect(() => listConfiguredQuotaProviders()).not.toThrow();
   });
+
+  it('coalesces concurrent refreshes by provider ID', async () => {
+    const first = fetchQuotaForProvider('unsupported-test-provider');
+    const second = fetchQuotaForProvider('unsupported-test-provider');
+
+    expect(first).toBe(second);
+    await first;
+    expect(fetchQuotaForProvider('unsupported-test-provider')).not.toBe(first);
+  });
 });