fix: Default Tenant-ID in UCCA + Maximizer Proxies

Die UCCA Assessment Proxies leiteten X-Tenant-ID nur weiter wenn
der Browser ihn explizit sendete. Da das Frontend den Header nicht
setzt, kam immer 400/leer zurueck. Alle anderen Proxies (compliance,
training, academy etc.) hatten bereits den Fallback auf DEFAULT_TENANT_ID.

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

admin-compliance/app/api/sdk/v1/maximizer/[[...path]]/route.ts

@@ -1,6 +1,8 @@
 import { NextRequest, NextResponse } from 'next/server'
 
 const SDK_URL = process.env.SDK_URL || 'http://ai-compliance-sdk:8090'
+const DEFAULT_TENANT_ID = process.env.DEFAULT_TENANT_ID || '9282a473-5c95-4b3a-bf78-0ecc0ec71d3e'
+const DEFAULT_USER_ID = '00000000-0000-0000-0000-000000000001'
 
 function buildUrl(request: NextRequest, params: { path?: string[] }) {
   const subPath = params.path?.join('/') || ''
@@ -11,10 +13,8 @@ function buildUrl(request: NextRequest, params: { path?: string[] }) {
 
 function forwardHeaders(request: NextRequest): Record<string, string> {
   const headers: Record<string, string> = { 'Content-Type': 'application/json' }
-  const tenantId = request.headers.get('X-Tenant-ID')
-  if (tenantId) headers['X-Tenant-ID'] = tenantId
-  const userId = request.headers.get('X-User-ID')
-  if (userId) headers['X-User-ID'] = userId
+  headers['X-Tenant-ID'] = request.headers.get('X-Tenant-ID') || DEFAULT_TENANT_ID
+  headers['X-User-ID'] = request.headers.get('X-User-ID') || DEFAULT_USER_ID
   return headers
 }