feat: consolidate execution paths and extract shared modules

- Created new reusable modules for platform integration, organization footprinting, scope validation, and checkpoint services
- Extracted 434 lines of duplicate code into shared modules that both Execute() and ExecuteWithPipeline() can use
- Added detailed implementation plan for merging execution paths while maintaining production stability
- Updated ROADMAP.md with investigation findings and Week 1 execution strategy
- Identified 5 critical

Author: CodeMonkeyCybersecurity