feat(banner): P19 + P20 — Per-Category-Click-Test + Frontend-Drilldown

P19 (consent-tester):
- dp-cookieconsent (TYPO3, Safetykon-Pattern) als CMP-Profil hinzu —
  Selektoren #dp--cookie-statistics/marketing + a.cc-allow Save-Button
- Neues Signal provider_details_visible: nach Kategorie-Toggle prueft
  Playwright ob im Banner sichtbare Provider-/Cookie-Detail-Elemente
  erscheinen. Bei dp-cookieconsent (Banner ohne Listing) immer False
  -> HIGH-Violation "Kategorie zeigt keine Provider-/Cookie-Details —
  Nutzer kann nicht informiert einwilligen (Art. 7 Abs. 1 DSGVO)"
- main.py serialisiert provider_details_visible + cookies_set pro Kategorie

P20 (Frontend-Drilldown):
- Backend: check_payloads-Tabelle um Spalte 'banner' (JSON) — voller
  banner_result persistiert (vorher nur in-memory). ALTER TABLE
  Migration idempotent.
- Neuer Endpoint GET /api/compliance/agent/banner/<check_id> — liefert
  Quality-Score, Phases, Category-Tests, Banner-Checks, alle 46
  structured_checks.
- Frontend: BannerTab im /sdk/agent/audit/<id> mit Quality-Cards,
  3-Phasen-Cookie-Tabelle, Per-Category-Listing (mit P19-Signal
  rot/gruen), Banner-Verstoesse + Rechtsgrundlagen, 46-Check-Drilldown
  filterbar nach Severity.
- Tab-Switcher in page.tsx um "Cookie-Banner-Analyse" erweitert.
- Bonus: 2 alte route.ts auf Next.js 15 Promise-params umgestellt
  (Build-Fix).

Plus: Critical-Findings-Block nutzt provider_details_visible als
primaeres Signal statt nur tracking_services-Anzahl.

Smoke-Test Safetykon: 4 Critical Findings im Mail, banner-Endpoint
liefert 46 checks + 3 phases + 2 categories mit provider_details_visible=False.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend-compliance/compliance/api/agent_findings_routes.py

@@ -24,7 +24,7 @@ from compliance.services.unified_findings_store import (
     findings_summary,
     list_findings,
 )
-from compliance.services.compliance_audit_log import get_check_run
+from compliance.services.compliance_audit_log import get_check_run, get_check_payload
 
 logger = logging.getLogger(__name__)
 
@@ -102,3 +102,18 @@ def get_findings(
             "count": 0,
             "findings": [],
         }
+
+
+@router.get("/banner/{check_id}")
+def get_banner_payload(check_id: str) -> dict:
+    """P20: full banner_result (phases, structured_checks, category_tests,
+    banner_checks.violations) fuer das Voll-Audit-Frontend.
+    """
+    try:
+        payload = get_check_payload(check_id) or {}
+        banner = payload.get("banner") or {}
+        return {"found": bool(banner), "check_id": check_id, "banner": banner}
+    except Exception as e:
+        logger.exception("get_banner_payload failed for %s", check_id)
+        return {"found": False, "check_id": check_id,
+                "error": str(e)[:200], "banner": {}}