feat: Package 4 Nachbesserungen — History-Tracking, Pagination, Frontend-Fixes

Backend:
- Migration 009: compliance_einwilligungen_consent_history Tabelle
- EinwilligungenConsentHistoryDB Modell (consent_id, action, version, ip, ua, source)
- _record_history() Helper: automatisch bei POST /consents (granted) + PUT /revoke (revoked)
- GET /consents/{id}/history Endpoint (vor revoke platziert für korrektes Routing)
- GET /consents: history-Array pro Eintrag (inline Sub-Query)
- 5 neue Tests (TestConsentHistoryTracking) — 32/32 bestanden

Frontend:
- consent/route.ts: limit+offset aus Frontend-Request weitergeleitet, total-Feld ergänzt
- Neuer Proxy consent/[id]/history/route.ts für GET /consents/{id}/history
- page.tsx: globalStats state + loadStats() (Backend /consents/stats für globale Zahlen)
- page.tsx: Stats-Kacheln auf globalStats umgestellt (nicht mehr page-relativ)
- page.tsx: history-Mapper: created_at→timestamp, consent_version→version
- page.tsx: loadStats() bei Mount + nach Revoke

Dokumentation:
- Developer Portal: neue API-Docs-Seite /api/einwilligungen (Consent + Legal Docs + Cookie Banner)
- developer-portal/app/api/page.tsx: Consent Management Abschnitt
- MkDocs: History-Endpoint, Pagination-Abschnitt, History-Tracking Abschnitt
- Deploy-Skript: scripts/apply_consent_history_migration.sh

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

admin-compliance/app/api/sdk/v1/einwilligungen/consent/[id]/history/route.ts

@@ -0,0 +1,53 @@
+/**
+ * API Route: Consent History
+ *
+ * GET /api/sdk/v1/einwilligungen/consent/{id}/history
+ * Proxies to backend-compliance: GET /api/compliance/einwilligungen/consents/{id}/history
+ */
+
+import { NextRequest, NextResponse } from 'next/server'
+
+const BACKEND_URL = process.env.BACKEND_URL || 'http://backend-compliance:8002'
+
+function getTenantId(request: NextRequest): string {
+  const uuidRegex = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i
+  const clientTenantId = request.headers.get('x-tenant-id') || request.headers.get('X-Tenant-ID')
+  return (clientTenantId && uuidRegex.test(clientTenantId))
+    ? clientTenantId
+    : (process.env.DEFAULT_TENANT_ID || '9282a473-5c95-4b3a-bf78-0ecc0ec71d3e')
+}
+
+/**
+ * GET /api/sdk/v1/einwilligungen/consent/{id}/history
+ * Gibt die Änderungshistorie einer Einwilligung zurück.
+ */
+export async function GET(
+  request: NextRequest,
+  { params }: { params: { id: string } }
+) {
+  try {
+    const tenantId = getTenantId(request)
+    const response = await fetch(
+      `${BACKEND_URL}/api/compliance/einwilligungen/consents/${params.id}/history`,
+      {
+        method: 'GET',
+        headers: {
+          'Content-Type': 'application/json',
+          'X-Tenant-ID': tenantId,
+        },
+        signal: AbortSignal.timeout(30000),
+      }
+    )
+
+    if (!response.ok) {
+      const errorText = await response.text()
+      return NextResponse.json({ error: errorText }, { status: response.status })
+    }
+
+    const data = await response.json()
+    return NextResponse.json(data)
+  } catch (error) {
+    console.error('Error fetching consent history:', error)
+    return NextResponse.json({ error: 'Failed to fetch consent history' }, { status: 500 })
+  }
+}

admin-compliance/app/api/sdk/v1/einwilligungen/consent/route.ts

@@ -106,10 +106,13 @@ export async function GET(request: NextRequest) {
       return NextResponse.json({ statistics: stats })
     }
 
-    // Fetch consents with optional user filter
+    // Fetch consents — forward pagination params from frontend
+    const limit = searchParams.get('limit') || '50'
+    const offset = searchParams.get('offset') || '0'
     const queryParams = new URLSearchParams()
     if (userId) queryParams.set('user_id', userId)
-    queryParams.set('limit', '50')
+    queryParams.set('limit', limit)
+    queryParams.set('offset', offset)
 
     const response = await fetch(
       `${BACKEND_URL}/api/compliance/einwilligungen/consents?${queryParams.toString()}`,
@@ -123,9 +126,10 @@ export async function GET(request: NextRequest) {
 
     const data = await response.json()
     return NextResponse.json({
+      total: data.total || 0,
       totalConsents: data.total || 0,
-      activeConsents: (data.consents || []).filter((c: { granted: boolean; revoked_at: string | null }) => c.granted && !c.revoked_at).length,
-      revokedConsents: (data.consents || []).filter((c: { revoked_at: string | null }) => c.revoked_at).length,
+      offset: data.offset || 0,
+      limit: data.limit || parseInt(limit),
       consents: data.consents || [],
     })
   } catch (error) {