Add workflow integration that imports from root project instead of copying.
This maintains single source of truth for workflow system.
Changes:
- workflow_loader.py imports from /workflow/executor/python/
- Uses plugins from /workflow/plugins/python/
- Created /workflow/plugins/python/packagerepo/ for app-specific plugins
- Created publish_artifact.json workflow definition
Architecture:
- Packagerepo imports workflow system, doesn't copy it
- Shared plugins (math, string, logic) available to all apps
- App-specific plugins go in root workflow/plugins/python/{app}/
Benefits:
- Single workflow engine for entire metabuilder project
- Updates to workflow system benefit all apps automatically
- Consistent workflow format across frontend and backend
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>