fix(quality): Ruff/CVE/TS-Fixes, 104 neue Tests, Complexity-Refactoring

- Ruff: 144 auto-fixes (unused imports, == None → is None), F821/F811/F841 manuell
- CVEs: python-multipart>=0.0.22, weasyprint>=68.0, pillow>=12.1.1, npm audit fix (0 vulns)
- TS: 5 tote Drafting-Engine-Dateien entfernt, allowed-facts/sanitizer/StepHeader/context fixes
- Tests: +104 (ISMS 58, Evidence 18, VVT 14, Generation 14) → 1449 passed
- Refactoring: collect_ci_evidence (F→A), row_to_response (E→A), extract_requirements (E→A)
- Dead Code: pca-platform, 7 Go-Handler, dsr_api.py, duplicate Schemas entfernt

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend-compliance/compliance/db/isms_repository.py

@@ -14,10 +14,9 @@ from datetime import datetime, date
 from typing import List, Optional, Dict, Any, Tuple
 
 from sqlalchemy.orm import Session as DBSession
-from sqlalchemy import func, and_, or_
 
 from .models import (
-    ISMSScopeDB, ISMSContextDB, ISMSPolicyDB, SecurityObjectiveDB,
+    ISMSScopeDB, ISMSPolicyDB, SecurityObjectiveDB,
     StatementOfApplicabilityDB, AuditFindingDB, CorrectiveActionDB,
     ManagementReviewDB, InternalAuditDB, AuditTrailDB, ISMSReadinessCheckDB,
     ApprovalStatusEnum, FindingTypeEnum, FindingStatusEnum, CAPATypeEnum