feat(compliance-check): integrate banner cross-check + extract to module

Add automatic banner check (Step 3b) and banner-vs-cookie cross-check
(Step 3c) to unified compliance check. Extract cross-check logic to
banner_cookie_cross_check.py to keep routes under 500 LOC.

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

backend-compliance/compliance/api/agent_compliance_check_routes.py

@@ -203,6 +203,44 @@ async def _run_compliance_check(check_id: str, req: ComplianceCheckRequest):
             results.append(result)
             total_findings += result.findings_count
 
+        # Step 3b: Banner-Check (automatic, uses first URL or homepage)
+        banner_result = None
+        banner_url = req.documents[0].url if req.documents and req.documents[0].url else ""
+        # Use the homepage (strip path) for banner check
+        if banner_url:
+            from urllib.parse import urlparse
+            parsed = urlparse(banner_url)
+            banner_url = f"{parsed.scheme}://{parsed.netloc}"
+        if banner_url:
+            _update(check_id, "Cookie-Banner wird geprueft...")
+            try:
+                async with httpx.AsyncClient(timeout=120.0) as client:
+                    resp = await client.post(
+                        f"{CONSENT_TESTER_URL}/scan",
+                        json={"url": banner_url, "timeout_per_phase": 10},
+                    )
+                    if resp.status_code == 200:
+                        banner_result = resp.json()
+            except Exception as e:
+                logger.warning("Banner check failed: %s", e)
+
+        # Step 3c: Cross-check Banner vs Cookie-Richtlinie
+        if banner_result and "cookie" in doc_texts:
+            _update(check_id, "Banner vs. Cookie-Richtlinie abgleichen...")
+            cross_findings = _cross_check_banner_vs_cookie(
+                banner_result, doc_texts["cookie"],
+            )
+            if cross_findings:
+                # Add cross-check findings to cookie results
+                for r in results:
+                    if r.doc_type == "cookie":
+                        for cf in cross_findings:
+                            r.checks.append(CheckItem(**cf))
+                        # Recompute
+                        l2 = [c for c in r.checks if c.level == 2 and not c.skipped]
+                        l2p = sum(1 for c in l2 if c.passed)
+                        r.correctness_pct = round(l2p / len(l2) * 100) if l2 else 0
+
         # Step 4: Build report
         _update(check_id, "Report wird erstellt...")
         report_html = build_html_report(results, None)
@@ -223,6 +261,11 @@ async def _run_compliance_check(check_id: str, req: ComplianceCheckRequest):
         response = {
             "results": [_result_to_dict(r) for r in results],
             "business_profile": profile_dict,
+            "banner_result": {
+                "detected": banner_result.get("banner_detected", False) if banner_result else False,
+                "provider": banner_result.get("banner_provider", "") if banner_result else "",
+                "violations": len(banner_result.get("banner_checks", {}).get("violations", [])) if banner_result else 0,
+            } if banner_result else None,
             "total_documents": len(results),
             "total_findings": total_findings,
             "email_status": email_result.get("status", "failed"),
@@ -437,3 +480,7 @@ def _build_profile_html(profile) -> str:
         f'<td>{int(profile.confidence * 100)}%</td></tr>'
         '</table></div>'
     )
+
+
+# Cross-check extracted to compliance.services.banner_cookie_cross_check
+from compliance.services.banner_cookie_cross_check import cross_check_banner_vs_cookie as _cross_check_banner_vs_cookie