[Backend] Support pipeline based scans
### Summary Security scan profiles with `merge_request_pipeline` or `default_branch_pipeline` triggers should automatically add scan jobs to pipelines and enable pipelines when no other configuration source exists. ### Requirements - Security scan profiles should add scan jobs to pipelines when configured with: - `merge_request_pipeline` trigger - `default_branch_pipeline` trigger - Pipelines should be automatically enabled if no other source is present: - No CI file configuration - No security policy configuration - No Auto DevOps configuration ### Scope **Phase 1 Focus: SAST** - Priority scanner: `gitlab-advanced-sast` ### Expected Behavior When a security scan profile is configured with the specified triggers and no other pipeline sources exist, we should: 1. Add the appropriate SAST scan jobs to the pipeline 2. Enable pipeline execution 3. Prioritize using the `gitlab-advanced-sast` scanner over other SAST scanners *** _Description was generated using AI_
issue