docs: update testing guide and sidebar documentation

- Add Testing Hub (Admin Dashboard) section to testing guide
  - Document features: collection, running tests, statistics
  - Document API endpoints and background execution
- Update sidebar documentation for new structure:
  - Add Product Catalog section
  - Add Platform Health section (Testing Hub, Code Quality, Background Tasks)
  - Update Settings to collapsible section
  - Update page-to-section mappings

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/testing/testing-guide.md

@@ -14,6 +14,7 @@ The Wizamart platform employs a comprehensive testing strategy with four distinc
 - [Mocking](#mocking)
 - [Best Practices](#best-practices)
 - [Troubleshooting](#troubleshooting)
+- [Testing Hub (Admin Dashboard)](#testing-hub-admin-dashboard)
 
 ---
 
@@ -1266,6 +1267,71 @@ If you encounter issues:
 
 ---
 
+## Testing Hub (Admin Dashboard)
+
+The platform includes a web-based Testing Hub accessible at `/admin/testing` that provides a visual interface for running tests and monitoring test health.
+
+### Accessing the Testing Hub
+
+Navigate to **Platform Health → Testing Hub** in the admin sidebar, or go directly to `/admin/testing`.
+
+### Features
+
+#### 1. Test Collection
+Click **Collect Tests** to discover all available tests in the codebase without running them. This displays:
+
+- **Total Tests**: Number of test functions discovered
+- **Unit Tests**: Tests in `tests/unit/`
+- **Integration Tests**: Tests in `tests/integration/`
+- **Performance Tests**: Tests in `tests/performance/`
+- **Test Files**: Number of test files
+
+#### 2. Running Tests
+Click **Run Tests** to execute the test suite. Tests run in the background, so you can:
+- Leave the page and return later
+- Monitor elapsed time in real-time
+- See results when tests complete
+
+#### 3. Dashboard Statistics
+The dashboard shows results from the last test run:
+
+- **Pass Rate**: Percentage of tests passing
+- **Passed/Failed/Errors**: Test outcome counts
+- **Duration**: How long the test run took
+- **Skipped**: Tests marked to skip
+
+#### 4. Trend Analysis
+View pass rate trends across the last 10 test runs to identify regressions.
+
+#### 5. Tests by Category
+See breakdown of passed/failed tests by category (Unit, Integration, etc.).
+
+#### 6. Top Failing Tests
+Quickly identify tests that fail most frequently across runs.
+
+### API Endpoints
+
+The Testing Hub uses these API endpoints:
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `/api/v1/admin/tests/stats` | GET | Dashboard statistics |
+| `/api/v1/admin/tests/run` | POST | Start a test run |
+| `/api/v1/admin/tests/runs` | GET | List recent test runs |
+| `/api/v1/admin/tests/runs/{id}` | GET | Get specific run details |
+| `/api/v1/admin/tests/collect` | POST | Collect test information |
+
+### Background Execution
+
+Test runs execute as background tasks, allowing:
+- Non-blocking UI during long test runs
+- Ability to navigate away and return
+- Automatic status polling every 2 seconds
+
+View all background tasks including test runs at **Platform Health → Background Tasks**.
+
+---
+
 ## Summary
 
 This testing guide covers:
@@ -1277,5 +1343,6 @@ This testing guide covers:
 - ✅ Mocking patterns and best practices
 - ✅ Best practices for maintainable tests
 - ✅ Troubleshooting common issues
+- ✅ Testing Hub admin dashboard
 
 For information about maintaining and extending the test suite, see [Test Maintenance Guide](test-maintenance.md).