refactor(backend/api): extract vendor compliance services (Step 4)
Split vendor_compliance_routes.py (1107 LOC) into thin route handlers plus three service modules: VendorService (vendors CRUD/stats/status), ContractService (contracts CRUD), and FindingService + ControlInstanceService + ControlsLibraryService (findings, control instances, controls library). All files under 500 lines. 215 tests pass. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in: