refactor: remove dead code, hollow stubs, and orphaned modules

Backend — delete 6 orphaned schema sub-modules never imported by any route:
  compliance/schemas/{ai_system,bsi,dashboard,isms_governance,report,service_module}.py
  All symbols were only accessible through the monolithic schemas.py barrel;
  the split files were never wired up and created misleading import paths.

Frontend — delete 2 hollow "future implementation" stub pages:
  app/sdk/agents/sessions/page.tsx
  app/sdk/agents/statistics/page.tsx
  Both showed a static placeholder with no API calls or real functionality.

Frontend — delete dead demo seed/clear API routes:
  app/api/sdk/v1/demo/{seed,clear}/route.ts
  Used a global in-memory store never connected to PostgreSQL.
  The actual demo seeding (lib/sdk/demo-data/) goes through the real
  state API (apiClient.saveState/deleteState), not these routes.

Frontend — remove unimplemented PDF export alert from retention page:
  app/sdk/einwilligungen/retention/page.tsx
  Removed the PDF button and alert('PDF-Export wird noch implementiert.')
  stub. CSV and JSON export remain fully functional.

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

admin-compliance/app/sdk/agents/sessions/page.tsx

@@ -1,34 +0,0 @@
-'use client'
-
-import React from 'react'
-import Link from 'next/link'
-
-export default function AgentSessionsPage() {
-  return (
-    <div className="p-8 max-w-5xl">
-      <div className="flex items-center gap-4 mb-8">
-        <Link href="/sdk/agents" className="text-gray-400 hover:text-gray-600 transition-colors">
-          <svg className="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M15 19l-7-7 7-7" />
-          </svg>
-        </Link>
-        <div>
-          <h1 className="text-2xl font-bold text-gray-900">Agent-Sessions</h1>
-          <p className="text-gray-500 mt-1">Chat-Verlaeufe und Session-Management</p>
-        </div>
-      </div>
-
-      <div className="bg-white border border-gray-200 rounded-xl p-12 text-center">
-        <svg className="w-20 h-20 text-gray-300 mx-auto mb-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={1.5}
-            d="M8 12h.01M12 12h.01M16 12h.01M21 12c0 4.418-4.03 8-9 8a9.863 9.863 0 01-4.255-.949L3 20l1.395-3.72C3.512 15.042 3 13.574 3 12c0-4.418 4.03-8 9-8s9 3.582 9 8z" />
-        </svg>
-        <h2 className="text-xl font-medium text-gray-900 mb-2">Sessions-Tracking</h2>
-        <p className="text-gray-500 max-w-md mx-auto">
-          Das Session-Tracking fuer Compliance-Agenten wird in einer zukuenftigen Version implementiert.
-          Hier werden Chat-Verlaeufe, Antwortqualitaet und Nutzer-Feedback angezeigt.
-        </p>
-      </div>
-    </div>
-  )
-}

admin-compliance/app/sdk/agents/statistics/page.tsx

@@ -1,34 +0,0 @@
-'use client'
-
-import React from 'react'
-import Link from 'next/link'
-
-export default function AgentStatisticsPage() {
-  return (
-    <div className="p-8 max-w-5xl">
-      <div className="flex items-center gap-4 mb-8">
-        <Link href="/sdk/agents" className="text-gray-400 hover:text-gray-600 transition-colors">
-          <svg className="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M15 19l-7-7 7-7" />
-          </svg>
-        </Link>
-        <div>
-          <h1 className="text-2xl font-bold text-gray-900">Agent-Statistiken</h1>
-          <p className="text-gray-500 mt-1">Performance-Metriken und Nutzungsanalysen</p>
-        </div>
-      </div>
-
-      <div className="bg-white border border-gray-200 rounded-xl p-12 text-center">
-        <svg className="w-20 h-20 text-gray-300 mx-auto mb-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={1.5}
-            d="M9 19v-6a2 2 0 00-2-2H5a2 2 0 00-2 2v6a2 2 0 002 2h2a2 2 0 002-2zm0 0V9a2 2 0 012-2h2a2 2 0 012 2v10m-6 0a2 2 0 002 2h2a2 2 0 002-2m0 0V5a2 2 0 012-2h2a2 2 0 012 2v14a2 2 0 01-2 2h-2a2 2 0 01-2-2z" />
-        </svg>
-        <h2 className="text-xl font-medium text-gray-900 mb-2">Agent-Statistiken</h2>
-        <p className="text-gray-500 max-w-md mx-auto">
-          Detaillierte Statistiken wie Antwortzeiten, Erfolgsraten, haeufigste Themen und
-          RAG-Trefferquoten werden in einer zukuenftigen Version implementiert.
-        </p>
-      </div>
-    </div>
-  )
-}

admin-compliance/app/sdk/einwilligungen/retention/page.tsx

@@ -274,7 +274,7 @@ function RetentionTimeline({ dataPoints, language }: RetentionTimelineProps) {
 // =============================================================================
 
 interface ExportOptionsProps {
-  onExport: (format: 'csv' | 'json' | 'pdf') => void
+  onExport: (format: 'csv' | 'json') => void
 }
 
 function ExportOptions({ onExport }: ExportOptionsProps) {
@@ -294,13 +294,6 @@ function ExportOptions({ onExport }: ExportOptionsProps) {
         <Download className="w-4 h-4" />
         JSON
       </button>
-      <button
-        onClick={() => onExport('pdf')}
-        className="flex items-center gap-2 px-3 py-2 bg-indigo-600 text-white rounded-lg text-sm hover:bg-indigo-700"
-      >
-        <Download className="w-4 h-4" />
-        PDF
-      </button>
     </div>
   )
 }
@@ -332,7 +325,7 @@ function RetentionContent() {
   }, [allDataPoints, filterCategory])
 
   // Handle export
-  const handleExport = (format: 'csv' | 'json' | 'pdf') => {
+  const handleExport = (format: 'csv' | 'json') => {
     if (format === 'csv') {
       const headers = ['Code', 'Name', 'Kategorie', 'Loeschfrist', 'Rechtsgrundlage']
       const rows = allDataPoints.map((dp) => [
@@ -354,8 +347,6 @@ function RetentionContent() {
         legalBasis: dp.legalBasis,
       }))
       downloadFile(JSON.stringify(data, null, 2), 'loeschfristen.json', 'application/json')
-    } else {
-      alert('PDF-Export wird noch implementiert.')
     }
   }