Fix audit finding F13:
src/data2dsl_subactor.py, replace loose substring matching for authority tokens (kw in tok) with exact token matching (tok in VALID_AUTHORITY_KEYWORDS) to prevent unauthorized tokens (e.g. unauthorized_autonomous) from passing validation.simulate_self_healing_cycle, fix the diagnostic severity summary dictionary access so that "diagnostic_severity_summary" receives the summary dictionary (diag_profile.get("summary")).SESSION_EXECUTION_AUTHORIZATION recorded from user prompt.
validate_delegation_envelope validates authority tokens using exact token equality against VALID_AUTHORITY_KEYWORDS.simulate_self_healing_cycle correctly captures diagnostic summary in "diagnostic_severity_summary".tests/test_subactor_f13.py pass.governance-check.bat reports GOV-PASS.