Restore explicit provenance imports in ImageTool

[kmnhan]

Summary

• Replaced globals().update(...) in provenance_operations.py with explicit imports from provenance_framework
• Removed module-level mypy and ruff suppressions from the provenance operations module
• Added a general AGENTS.md rule to avoid mutating globals() in library modules

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.89%. Comparing base (f966c25) to head (f6d4026).
⚠️ Report is 3 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #377   +/-   ##
=======================================
  Coverage   88.89%   88.89%           
=======================================
  Files         139      139           
  Lines       47155    47166   +11     
  Branches     7588     7592    +4     
=======================================
+ Hits        41918    41928   +10     
  Misses       3271     3271           
- Partials     1966     1967    +1     

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