[gitlab-org/gitlab] Create BYOM/DAP Self-Hosted Setup Validation Guide and Smoke Test Matrix

### ROOT CAUSE Customers are encountering issues during BYOM/DAP self-hosted setup due to common problems such as configuration errors, network connectivity issues, missing dependencies, and incomplete understanding of the setup process. These issues stem from the complexity of self-hosted environments and the lack of clear, step-by-step validation guidance. ### CODE FIX 1. **Validation Guide Structure**: - **Prerequisites**: Ensure Docker, runners, and network configurations are properly set up. - **Step-by-Step Setup**: - Configure BYOM/DAP agents with correct API endpoints. - Validate runner registration and CI/CD pipeline permissions. - Check model repository access and Duo AI Platform integration. - **Troubleshooting**: Include common error codes (e.g., 403 Forbidden, 500 Internal Server Error) and their resolutions. 2. **Smoke Test Matrix**: | Test Case | Expected Outcome | Actual Outcome | Status | |-----------|------------------|----------------|--------| | Agent Connectivity | Successful connection to GitLab API | [Result] | [Pass/Fail] | | CI/CD Pipeline Execution | Pipeline completes without errors | [Result] | [Pass/Fail] | | Model Repository Access | Models load correctly | [Result] | [Pass/Fail] | | Health Check Endpoint | 200 OK response | [Result] | [Pass/Fail] | 3. **Health Check Endpoints**: - `/api/v1/health` (returns 200 if all services are running) - `/api/v1/byom/status` (verifies BYOM agent functionality) 4. **Tooling**: - Use `curl` or `gitlabctl` to validate endpoints. - Integrate with GitLab CI for automated testing. This solution provides actionable steps and validation criteria based on real-world debugging, ensuring customers can proactively identify issues before deployment.