feat: add compliance module with FREE-AI reporting

[shivdeep1]

Summary

• Add airlock/compliance/ module with agent inventory, risk classification, incident tracking, bias detection, and compliance report generation mapped to RBI FREE-AI 7 Sutras and 26 recommendations
• Add 9 gateway API endpoints under /compliance/ for inventory CRUD, risk assessment, incident reporting, and compliance report generation
• Add 45 tests covering unit and route tests for all compliance components (805 total tests passing, zero regressions)

Test plan

• pytest tests/test_compliance_inventory.py tests/test_compliance_reports.py tests/test_risk_classifier.py -x -- 45 tests pass
• pytest tests/ -x -- 805 tests pass (no regressions)
• ruff check airlock/compliance/ airlock/gateway/compliance_routes.py -- clean