feat: Phase 3 — registry 82 services, mandatory checker, SDK flow step

- website_scanner.py: imports from master service_registry.py (82 services)
- agent_scan_routes.py: mandatory content checks (documents + DSE sections)
- steps-betrieb.ts: Compliance Agent step added to SDK Flow (seq 5000)
- PLAN: Phase 9 (Authenticated Testing) added to product roadmap

Mandatory checks know what MUST be there:
- Documents: Impressum, DSE, AGB, Widerrufsbelehrung
- DSE content: 9 Art. 13 DSGVO fields (DSB, Speicherdauer, etc.)
- Impressum content: 5 §5 TMG fields (GF, HRB, USt-ID, etc.)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend-compliance/compliance/api/agent_scan_routes.py

@@ -18,6 +18,9 @@ from compliance.services.dse_service_extractor import extract_dse_services, comp
 from compliance.services.smtp_sender import send_email
 from compliance.services.dse_parser import parse_dse
 from compliance.services.dse_matcher import build_text_references, TextReference
+from compliance.services.mandatory_content_checker import (
+    check_mandatory_documents, check_dse_mandatory_content, MandatoryFinding,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -120,7 +123,16 @@ async def scan_website_endpoint(req: ScanRequest):
     # Step 7: Generate findings with text references
     services_info, findings = _build_findings(comparison, scan, is_live, text_refs)
 
-    # Step 8: Generate corrections for pre-launch mode
+    # Step 8: Check mandatory content (documents + DSE sections)
+    mandatory_findings = check_mandatory_documents(scan.pages_scanned, scan.missing_pages)
+    mandatory_findings += check_dse_mandatory_content(dse_sections, dse_text)
+    for mf in mandatory_findings:
+        findings.append(ScanFinding(
+            code=mf.code, severity=mf.severity,
+            text=f"{mf.text}" + (f" — {mf.suggestion}" if mf.suggestion else ""),
+        ))
+
+    # Step 9: Generate corrections for pre-launch mode
     if not is_live and findings:
         await _add_corrections(findings, dse_text)