fix: scope governance suppression to same line

[CoderDeltaLAN]

Summary:

• Scopes context-aware governance suppression to same-line negation or approval cues.
• Prevents adjacent safe guidance from hiding a separate risky instruction line.
• Updates regression tests and rule documentation for the narrower suppression boundary.

Verification:

• Reproduction now reports AIRK-GOV003 for an unrelated adjacent dangerous line.
• Targeted governance and CLI tests passed.
• Full local check passed: 118 tests, Ruff, text hygiene, git whitespace.
• Secret-like pattern scan passed.

Scope:

• CHANGELOG.md
• docs/RULES.md
• src/agent_rules_kit/governance.py
• tests/test_governance.py