Add basic Poetry environment lifecycle support

[Eduardo Villalpando Mello (edvilme)]

Summary

• add basic Poetry environment creation for existing projects using a selected global Python 3 interpreter
• add Poetry environment removal with owning-project detection and selection/cache cleanup
• add lifecycle unit coverage for creation, package failures, reused environments, removal, and multi-project associations

Validation

• npm run lint
• npm run compile-tests
• npm run unittest