test: Add security audit and base workflow tests

Added comprehensive test suites for:
- SecurityAuditWorkflow: 34 tests covering OWASP patterns, team
  decisions, triage scanning, and LLM call handling
- BaseWorkflow: 24 tests covering enums, dataclasses, and model
  mappings

Coverage improvements:
- security_audit.py: 8.5% → 40%
- base.py: 28% (dataclass/enum coverage)

Total new tests: 58

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: 2 people