[split-required] Split final batch of monoliths >1000 LOC

Python (6 files in klausur-service):
- rbac.py (1,132 → 4), admin_api.py (1,012 → 4)
- routes/eh.py (1,111 → 4), ocr_pipeline_geometry.py (1,105 → 5)

Python (2 files in backend-lehrer):
- unit_api.py (1,226 → 6), game_api.py (1,129 → 5)

Website (6 page files):
- 4x klausur-korrektur pages (1,249-1,328 LOC each) → shared components
  in website/components/klausur-korrektur/ (17 shared files)
- companion (1,057 → 10), magic-help (1,017 → 8)

All re-export barrels preserve backward compatibility.
Zero import errors verified.

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

website/components/klausur-korrektur/ListTabNav.tsx

@@ -0,0 +1,69 @@
+'use client'
+
+/**
+ * Tab navigation bar for the Klausur-Korrektur list page.
+ */
+
+import type { TabId } from './list-types'
+
+interface TabDef {
+  id: TabId
+  name: string
+  icon: JSX.Element
+  hidden?: boolean
+}
+
+const tabs: TabDef[] = [
+  {
+    id: 'willkommen', name: 'Start',
+    icon: <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M3 12l2-2m0 0l7-7 7 7M5 10v10a1 1 0 001 1h3m10-11l2 2m-2-2v10a1 1 0 01-1 1h-3m-6 0a1 1 0 001-1v-4a1 1 0 011-1h2a1 1 0 011 1v4a1 1 0 001 1m-6 0h6" /></svg>,
+  },
+  {
+    id: 'klausuren', name: 'Klausuren',
+    icon: <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" /></svg>,
+  },
+  {
+    id: 'erstellen', name: 'Neue Klausur',
+    icon: <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 4v16m8-8H4" /></svg>,
+  },
+  {
+    id: 'direktupload', name: 'Schnellstart', hidden: true,
+    icon: <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M7 16a4 4 0 01-.88-7.903A5 5 0 1115.9 6L16 6a5 5 0 011 9.9M15 13l-3-3m0 0l-3 3m3-3v12" /></svg>,
+  },
+  {
+    id: 'statistiken', name: 'Statistiken',
+    icon: <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} 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>,
+  },
+]
+
+interface ListTabNavProps {
+  activeTab: TabId
+  onTabChange: (tab: TabId) => void
+  markAsVisited: () => void
+}
+
+export default function ListTabNav({ activeTab, onTabChange, markAsVisited }: ListTabNavProps) {
+  return (
+    <div className="border-b border-slate-200 mb-6">
+      <nav className="flex gap-4">
+        {tabs.filter(tab => !tab.hidden).map((tab) => (
+          <button
+            key={tab.id}
+            onClick={() => {
+              if (tab.id !== 'willkommen') markAsVisited()
+              onTabChange(tab.id)
+            }}
+            className={`flex items-center gap-2 px-4 py-3 text-sm font-medium border-b-2 transition-colors ${
+              activeTab === tab.id
+                ? 'border-primary-500 text-primary-600'
+                : 'border-transparent text-slate-500 hover:text-slate-700 hover:border-slate-300'
+            }`}
+          >
+            {tab.icon}
+            {tab.name}
+          </button>
+        ))}
+      </nav>
+    </div>
+  )
+}