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/services/audit_pdf_generator.py

@@ -18,27 +18,23 @@ import io
 import logging
 from datetime import datetime
 from typing import Dict, List, Any, Optional, Tuple
-from uuid import uuid4
-import hashlib
 
-from sqlalchemy.orm import Session, selectinload
+from sqlalchemy.orm import Session
 
 from reportlab.lib import colors
 from reportlab.lib.pagesizes import A4
 from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
-from reportlab.lib.units import mm, cm
-from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_RIGHT, TA_JUSTIFY
+from reportlab.lib.units import mm
+from reportlab.lib.enums import TA_CENTER, TA_JUSTIFY
 from reportlab.platypus import (
     SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
-    PageBreak, Image, ListFlowable, ListItem, KeepTogether,
-    HRFlowable
+    PageBreak, HRFlowable
 )
-from reportlab.graphics.shapes import Drawing, Rect, String
+from reportlab.graphics.shapes import Drawing
 from reportlab.graphics.charts.piecharts import Pie
 
 from ..db.models import (
-    AuditSessionDB, AuditSignOffDB, AuditResultEnum, AuditSessionStatusEnum,
-    RequirementDB, RegulationDB
+    AuditSessionDB, AuditSignOffDB, AuditResultEnum, RequirementDB, RegulationDB
 )
 
 logger = logging.getLogger(__name__)