Implement git-flow native release process with AI summary integration (refs #20)

- Create gitflow-release.zsh: Native git-flow release script with branch validation
- Create gitflow-monitor.zsh: Git-flow optimized monitoring with enhanced reporting
- Add AI_RELEASE_SUMMARY_INTEGRATION.md: Comprehensive analysis and implementation guide
- Integrate AI release summary at release branch creation point (optimal integration)
- Add enhanced validation for summary content and git-flow state
- Support for release preparation, dry run validation, and release finishing
- Include git-flow specific status reporting and recommendations
- Provide complete workflow examples for release and hotfix processes
- Add branch-specific validation and error handling
- Include implementation checklist for phased rollout

Author: fxstein