Harden AI session rules and tooling

[woksin]

Summary

Keep AI work records local without granting incidental permission to move or commit unrelated tracked files.

Changed

• Require an authorized follow-up before cleaning up an already-tracked work record discovered during another task.

Verification

• Scoped diff and whitespace checks passed; only AGENTS.md changes.
• Python package tests, typechecking, and builds were not run locally for this instruction-only change. Required hosted checks and code-owner review remain in force.