feat: Session policy pinning + tool alias registry

[imran-siddique]

Summary

Two adversarial-durability fixes for the governance layer:

Session Policy Pinning (Closes #92)

• \create_context()\ now deep-copies the policy so each session gets an immutable snapshot
• Prevents mid-session policy mutations from leaking into running sessions
• Documents that \pre_execute()\ still reads the live integration policy (follow-up needed)

Tool Alias Registry (Closes #94)

• New \ToolAliasRegistry\ class that maps tool name variants to canonical capability identifiers
• Default mappings for 7 tool families: web_search, file_read/write, shell_execute, code_execute, database_query, http_request
• Supports exact-match aliases AND regex pattern-based matching
• \is_allowed()\ / \is_blocked()\ canonicalize both sides before comparison
• Prevents policy bypass via tool renaming (e.g., \�ing_search\ bypassing a \web_search\ block)

Tests

• 20 tests covering pinning isolation, alias resolution, bypass prevention, pattern matching, and family coverage

Files Changed

• \�ase.py: Added \import copy, deep-copy in \create_context()\
• \ ool_aliases.py: New \ToolAliasRegistry\ class (166 lines)
• _init_.py: Export \ToolAliasRegistry\
• \ est_session_pinning_and_aliases.py: 20 tests

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None