feat: add GitLab CI and pre-commit hook support

[leoneperdigao]

Description

Extend CI/CD support beyond GitHub Actions to include GitLab CI, pre-commit hooks, and generic CI scripts that work with Jenkins, CircleCI, Azure Pipelines, and other CI systems. This broadens adoption by supporting the most common CI/CD platforms.

Tasks

• Create GitLab CI template:
  • .gitlab-ci.yml template with scanning stage
  • Support for GitLab Code Quality report format
  • MR (merge request) comment with scan summary
  • Configurable failure thresholds via CI variables
  • Artifact upload for scan results
• Implement pre-commit hook:
  • .pre-commit-hooks.yaml for pre-commit framework integration
  • Fast scan mode for commit-time checks (source code only)
  • Configurable severity threshold for blocking commits
  • Support --files flag for scanning only staged files
• Create generic CI scripts:
  • Shell script (run-scan.sh) for Jenkins, CircleCI, Azure Pipelines
  • Support environment variable configuration
  • JUnit XML output for CI test result integration
  • Generic exit code conventions for threshold-based failure
• Define exit code standards:
  • 0: No findings above threshold
  • 1: Findings above threshold (pipeline should fail)
  • 2: Scanner error / misconfiguration
• Write documentation for each CI platform setup
• Add example configurations for each supported platform

References

• GitLab CI Templates
• pre-commit framework
• Jenkins Pipeline