[codex] Add skill import project mode

[zack-dev-cm]

Summary

• add Skill Import Project Mode for adapting upstream skill repositories and workflows
• require source inventory, PORT/REWRITE/REJECT classification, staging, duplicate-name checks, public-surface scans, and explicit approval before install or publish
• refresh public-surface tests for the current 0.3.4 metadata

Validation

• python3 -m unittest discover -s tests
• clawhub inspect agentic-codex-dev --files

Not run

• python3 -m antirot.cli lint SKILL.md --strict: antirot is not installed
• python3 -m codex_harness audit . --strict --min-score 90: codex_harness is not installed