fix: load claude models directly from provider

Claude's model catalog changes quickly enough that a shared three-day cache can
leave users selecting stale defaults or missing newly available model aliases.
Route Claude model lookups through the provider every time so the UI and slash
commands reflect the current provider result instead of an old disk snapshot.

Keep the static fallback catalog aligned with the latest Claude defaults so the
provider still has a sensible response when live discovery is unavailable.

server/modules/providers/tests/provider-models.service.test.ts

@@ -130,6 +130,37 @@ test('provider models are cached for the three-day ttl', async () => {
   }
 });
 
+test('claude provider models are always loaded directly from the provider', async () => {
+  const tempRoot = await mkdtemp(path.join(os.tmpdir(), 'provider-model-cache-claude-direct-'));
+  let loadCount = 0;
+
+  try {
+    const service = createProviderModelsService({
+      cachePath: path.join(tempRoot, 'models-cache.json'),
+      resolveProvider: (provider) => ({
+        models: {
+          getSupportedModels: async () => {
+            loadCount += 1;
+            return createModels(`${provider}-${loadCount}`);
+          },
+          getCurrentActiveModel: async () => createCurrentActiveModel(`${provider}-active`),
+          changeActiveModel: async (input) => createSessionActiveModelChange(provider, input),
+        },
+      }),
+    });
+
+    const first = await service.getProviderModels('claude');
+    const second = await service.getProviderModels('claude');
+
+    assert.equal(loadCount, 2);
+    assert.equal(first.models.DEFAULT, 'claude-1');
+    assert.equal(second.models.DEFAULT, 'claude-2');
+    assert.equal(second.cache.source, 'fresh');
+  } finally {
+    await rm(tempRoot, { recursive: true, force: true });
+  }
+});
+
 test('provider model cache is persisted across service instances', async () => {
   const tempRoot = await mkdtemp(path.join(os.tmpdir(), 'provider-model-cache-file-'));
   const cachePath = path.join(tempRoot, 'models-cache.json');