[split-required] Split 500-850 LOC files (batch 2)

backend-lehrer (10 files):
- game/database.py (785 → 5), correction_api.py (683 → 4)
- classroom_engine/antizipation.py (676 → 5)
- llm_gateway schools/edu_search already done in prior batch

klausur-service (12 files):
- orientation_crop_api.py (694 → 5), pdf_export.py (677 → 4)
- zeugnis_crawler.py (676 → 5), grid_editor_api.py (671 → 5)
- eh_templates.py (658 → 5), mail/api.py (651 → 5)
- qdrant_service.py (638 → 5), training_api.py (625 → 4)

website (6 pages):
- middleware (696 → 8), mail (733 → 6), consent (628 → 8)
- compliance/risks (622 → 5), export (502 → 5), brandbook (629 → 7)

studio-v2 (3 components):
- B2BMigrationWizard (848 → 3), CleanupPanel (765 → 2)
- dashboard-experimental (739 → 2)

admin-lehrer (4 files):
- uebersetzungen (769 → 4), manager (670 → 2)
- ChunkBrowserQA (675 → 6), dsfa/page (674 → 5)

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

website/app/mail/_components/MailSidebar.tsx

@@ -0,0 +1,106 @@
+'use client'
+
+import type { Account, Folder } from './types'
+import { FOLDER_LABELS } from './types'
+
+interface MailSidebarProps {
+  folders: Folder[]
+  accounts: Account[]
+  selectedFolder: string
+  setSelectedFolder: (folder: string) => void
+  selectedAccount: string
+  setSelectedAccount: (account: string) => void
+  totalUnread: number
+}
+
+export default function MailSidebar({
+  folders,
+  accounts,
+  selectedFolder,
+  setSelectedFolder,
+  selectedAccount,
+  setSelectedAccount,
+  totalUnread,
+}: MailSidebarProps) {
+  return (
+    <aside className="w-64 bg-white border-r border-slate-200 flex flex-col">
+      {/* Folders */}
+      <nav className="p-4 space-y-1">
+        {folders.map((folder) => (
+          <button
+            key={folder.name}
+            onClick={() => setSelectedFolder(folder.name)}
+            className={`w-full flex items-center gap-3 px-3 py-2 rounded-lg text-left transition-colors ${
+              selectedFolder === folder.name
+                ? 'bg-primary-50 text-primary-700'
+                : 'text-slate-600 hover:bg-slate-50'
+            }`}
+          >
+            {folder.icon}
+            <span className="font-medium">{FOLDER_LABELS[folder.name]}</span>
+            {folder.count !== undefined && (
+              <span className="ml-auto text-sm text-slate-500">{folder.count}</span>
+            )}
+          </button>
+        ))}
+      </nav>
+
+      <div className="border-t border-slate-200 my-2"></div>
+
+      {/* Accounts */}
+      <div className="p-4">
+        <h3 className="text-xs font-semibold text-slate-500 uppercase tracking-wider mb-3">
+          Konten
+        </h3>
+        <div className="space-y-1">
+          <button
+            onClick={() => setSelectedAccount('all')}
+            className={`w-full flex items-center gap-3 px-3 py-2 rounded-lg text-left transition-colors ${
+              selectedAccount === 'all'
+                ? 'bg-primary-50 text-primary-700'
+                : 'text-slate-600 hover:bg-slate-50'
+            }`}
+          >
+            <div className="w-2 h-2 bg-gradient-to-r from-blue-500 to-purple-500 rounded-full"></div>
+            <span className="font-medium text-sm">Alle Konten</span>
+            <span className="ml-auto text-xs text-slate-500">{totalUnread}</span>
+          </button>
+          {accounts.map((account) => (
+            <button
+              key={account.id}
+              onClick={() => setSelectedAccount(account.id)}
+              className={`w-full flex items-center gap-3 px-3 py-2 rounded-lg text-left transition-colors ${
+                selectedAccount === account.id
+                  ? 'bg-primary-50 text-primary-700'
+                  : 'text-slate-600 hover:bg-slate-50'
+              }`}
+            >
+              <div className="w-2 h-2 bg-blue-500 rounded-full"></div>
+              <span className="font-medium text-sm truncate flex-1">
+                {account.displayName || account.email.split('@')[0]}
+              </span>
+              {account.unreadCount > 0 && (
+                <span className="text-xs bg-primary-100 text-primary-700 px-1.5 py-0.5 rounded">
+                  {account.unreadCount}
+                </span>
+              )}
+            </button>
+          ))}
+        </div>
+      </div>
+
+      {/* Quick Links */}
+      <div className="mt-auto p-4 border-t border-slate-200">
+        <a
+          href="/mail/tasks"
+          className="flex items-center gap-3 px-3 py-2 text-slate-600 hover:bg-slate-50 rounded-lg"
+        >
+          <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2" />
+          </svg>
+          <span className="font-medium text-sm">Arbeitsvorrat</span>
+        </a>
+      </div>
+    </aside>
+  )
+}