🧪 ci: Resolve DataTable test infinite re-render (#13947)

DataTable.spec failed with "Too many re-renders" (35 tests). Root cause: @tanstack/react-virtual is measurement-driven, and jsdom has no real layout, so its re-render loop never converges. This went unnoticed because packages/client had no jest CI job (only the client workspace runs jest in frontend-review.yml).

- DataTable: only read the virtualizer (getVirtualItems/getTotalSize) when virtualization is active; the non-virtualized branch renders rows directly, so engaging it for small tables was wasted render-phase work.
- Spec: mock @tanstack/react-virtual, since jsdom can't exercise real virtualization layout.
- Add a test:ci script to @librechat/client and a Tests: @librechat/client CI job so packages/client specs run on every frontend PR.

.github/workflows/frontend-review.yml

@@ -122,6 +122,44 @@ jobs:
         run: npm run typecheck
         working-directory: client
 
+  test-packages-client:
+    name: 'Tests: @librechat/client'
+    needs: build
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Use Node.js 24.16.0
+        uses: actions/setup-node@v4
+        with:
+          node-version: '24.16.0'
+
+      - name: Restore node_modules cache
+        id: cache-node-modules
+        uses: actions/cache@v4
+        with:
+          path: |
+            node_modules
+            client/node_modules
+            packages/client/node_modules
+            packages/data-provider/node_modules
+          key: node-modules-frontend-${{ runner.os }}-24.16.0-${{ hashFiles('package-lock.json') }}
+
+      - name: Install dependencies
+        if: steps.cache-node-modules.outputs.cache-hit != 'true'
+        run: npm ci
+
+      - name: Download data-provider build
+        uses: actions/download-artifact@v4
+        with:
+          name: build-data-provider
+          path: packages/data-provider/dist
+
+      - name: Run unit tests
+        run: npm run test:ci
+        working-directory: packages/client
+
   test-ubuntu:
     name: 'Tests: Ubuntu (shard ${{ matrix.shard }}/4)'
     needs: build