agent-07 phase 2: fix test isolation + CSV import UI

- Fix conftest.py: commit after each request in override_get_db so
  preview_csv's rollback no longer wipes the shared registered_user
  (root cause of 401 cascade across test_user_import + test_personnel_number)
- Fix limiter.enabled=False in client fixture (blocks rate-limit 429)
- Fix user_import_service: allow reactivation when personnel number
  belongs to the same user being reactivated
- Fix test_personnel_number: use PATCH /companies/me (not /companies/{id})
  and add try/finally cleanup for personnel_number_required flag
- Frontend UsersPage: add CSV import modal with template download,
  preview/validation table, and guarded apply button

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

frontend/src/pages/UsersPage.tsx

@@ -85,6 +85,22 @@ interface InviteForm {
 
 const EMPTY_INVITE: InviteForm = { email: '', first_name: '', last_name: '', role: 'EMPLOYEE', personnel_number: '', initial_password: '' }
 
+interface ImportRowResult {
+  row: number
+  email: string
+  personnel_number: string | null
+  action: string
+  message: string | null
+}
+
+interface ImportResult {
+  total_rows: number
+  created: number
+  reactivated: number
+  errors: number
+  items: ImportRowResult[]
+}
+
 export function UsersPage() {
   const [me, setMe]           = useState<Me | null>(null)
   const [users, setUsers]     = useState<UserOut[]>([])
@@ -118,6 +134,14 @@ export function UsersPage() {
   // Company-Settings (für Auto-Modus / Pflicht-Anzeige)
   const [company, setCompany] = useState<CompanyOut | null>(null)
 
+  // CSV-Import modal
+  const [showImport, setShowImport]         = useState(false)
+  const [importFile, setImportFile]         = useState<File | null>(null)
+  const [importPreview, setImportPreview]   = useState<ImportResult | null>(null)
+  const [importLoading, setImportLoading]   = useState(false)
+  const [importError, setImportError]       = useState('')
+  const [importSuccess, setImportSuccess]   = useState('')
+
   async function load() {
     try {
       const [meData, listData, schedulesData] = await Promise.all([
@@ -251,6 +275,51 @@ export function UsersPage() {
     return () => clearTimeout(handle)
   }
 
+  async function handleImportPreview() {
+    if (!importFile) return
+    setImportLoading(true)
+    setImportError('')
+    setImportPreview(null)
+    try {
+      const form = new FormData()
+      form.append('file', importFile)
+      const result = await api.postForm<ImportResult>('/users/import/preview', form)
+      setImportPreview(result)
+    } catch (e: unknown) {
+      setImportError(e instanceof Error ? e.message : 'Fehler beim Prüfen')
+    } finally {
+      setImportLoading(false)
+    }
+  }
+
+  async function handleImportApply() {
+    if (!importFile) return
+    setImportLoading(true)
+    setImportError('')
+    setImportSuccess('')
+    try {
+      const form = new FormData()
+      form.append('file', importFile)
+      const result = await api.postForm<ImportResult>('/users/import/apply', form)
+      setImportSuccess(`Import abgeschlossen: ${result.created} angelegt, ${result.reactivated} reaktiviert, ${result.errors} Fehler.`)
+      setImportPreview(result)
+      setImportFile(null)
+      load()
+    } catch (e: unknown) {
+      setImportError(e instanceof Error ? e.message : 'Fehler beim Import')
+    } finally {
+      setImportLoading(false)
+    }
+  }
+
+  function openImportModal() {
+    setShowImport(true)
+    setImportFile(null)
+    setImportPreview(null)
+    setImportError('')
+    setImportSuccess('')
+  }
+
   const filtered = users.filter(u =>
     `${u.full_name} ${u.email} ${u.personnel_number ?? ''}`.toLowerCase().includes(search.toLowerCase())
   )
@@ -275,12 +344,20 @@ export function UsersPage() {
             <h1 className='text-xl font-bold text-gray-800'>Mitarbeiterverwaltung</h1>
             <p className='text-sm text-gray-500 mt-0.5'>{total} Mitarbeiter gesamt</p>
           </div>
-          <button
-            onClick={() => { setShowInvite(true); setInviteSuccess(''); setInviteError('') }}
-            className='px-4 py-2 bg-blue-600 text-white text-sm font-semibold rounded-lg hover:bg-blue-700 transition-colors'
-          >
-            + Einladen
-          </button>
+          <div className='flex gap-2'>
+            <button
+              onClick={openImportModal}
+              className='px-4 py-2 bg-gray-100 text-gray-700 text-sm font-semibold rounded-lg hover:bg-gray-200 transition-colors border border-gray-200'
+            >
+              CSV Import
+            </button>
+            <button
+              onClick={() => { setShowInvite(true); setInviteSuccess(''); setInviteError('') }}
+              className='px-4 py-2 bg-blue-600 text-white text-sm font-semibold rounded-lg hover:bg-blue-700 transition-colors'
+            >
+              + Einladen
+            </button>
+          </div>
         </div>
 
         {/* Search */}
@@ -480,6 +557,103 @@ export function UsersPage() {
         </Modal>
       )}
 
+      {/* CSV Import Modal */}
+      {showImport && (
+        <Modal title='Mitarbeiter per CSV importieren' onClose={() => setShowImport(false)}>
+          <div className='space-y-4'>
+            <div className='flex items-center justify-between bg-blue-50 border border-blue-100 rounded-lg px-3 py-2'>
+              <span className='text-xs text-blue-700'>Vorlage mit Pflicht- und Optionalspalten herunterladen</span>
+              <a
+                href='/api/v1/users/import-template.csv'
+                download='import-vorlage.csv'
+                className='text-xs font-semibold text-blue-600 hover:underline ml-4 whitespace-nowrap'
+              >
+                Vorlage herunterladen
+              </a>
+            </div>
+
+            <div>
+              <label className='block text-xs font-medium text-gray-700 mb-1'>CSV-Datei auswählen</label>
+              <input
+                type='file'
+                accept='.csv,text/csv'
+                onChange={e => {
+                  setImportFile(e.target.files?.[0] ?? null)
+                  setImportPreview(null)
+                  setImportError('')
+                  setImportSuccess('')
+                }}
+                className='block w-full text-sm text-gray-600 file:mr-3 file:py-1.5 file:px-3 file:rounded file:border-0 file:text-xs file:font-semibold file:bg-blue-50 file:text-blue-700 hover:file:bg-blue-100'
+              />
+            </div>
+
+            {importError && <p className='text-sm text-red-600 bg-red-50 border border-red-200 rounded px-3 py-2'>{importError}</p>}
+            {importSuccess && <p className='text-sm text-green-700 bg-green-50 border border-green-200 rounded px-3 py-2'>{importSuccess}</p>}
+
+            {importPreview && (
+              <div className='space-y-2'>
+                <div className='flex gap-4 text-sm'>
+                  <span className='text-green-700 font-medium'>{importPreview.created} neu</span>
+                  <span className='text-blue-700 font-medium'>{importPreview.reactivated} reaktiviert</span>
+                  <span className='text-red-600 font-medium'>{importPreview.errors} Fehler</span>
+                  <span className='text-gray-500'>{importPreview.total_rows} Zeilen gesamt</span>
+                </div>
+                <div className='max-h-56 overflow-y-auto border border-gray-200 rounded-lg'>
+                  <table className='w-full text-xs'>
+                    <thead className='bg-gray-50 text-gray-500 sticky top-0'>
+                      <tr>
+                        {['Zeile', 'E-Mail', 'Pers.-Nr.', 'Aktion', 'Meldung'].map(h => (
+                          <th key={h} className='px-3 py-2 text-left font-medium'>{h}</th>
+                        ))}
+                      </tr>
+                    </thead>
+                    <tbody className='divide-y divide-gray-100'>
+                      {importPreview.items.map((it, i) => (
+                        <tr key={i} className={it.action === 'error' ? 'bg-red-50' : it.action === 'reactivated' ? 'bg-blue-50' : ''}>
+                          <td className='px-3 py-1.5 text-gray-500'>{it.row || '—'}</td>
+                          <td className='px-3 py-1.5 font-mono'>{it.email || '—'}</td>
+                          <td className='px-3 py-1.5 font-mono'>{it.personnel_number || '—'}</td>
+                          <td className='px-3 py-1.5'>
+                            <span className={`font-semibold ${
+                              it.action === 'error' ? 'text-red-600' :
+                              it.action === 'reactivated' ? 'text-blue-600' :
+                              'text-green-600'
+                            }`}>
+                              {it.action === 'error' ? 'Fehler' : it.action === 'reactivated' ? 'Reaktiviert' : 'Neu'}
+                            </span>
+                          </td>
+                          <td className='px-3 py-1.5 text-gray-500'>{it.message || ''}</td>
+                        </tr>
+                      ))}
+                    </tbody>
+                  </table>
+                </div>
+              </div>
+            )}
+
+            <div className='flex justify-end gap-2 pt-1'>
+              <button onClick={() => setShowImport(false)} className='px-4 py-2 text-sm text-gray-600 border border-gray-300 rounded-lg hover:bg-gray-50'>Schließen</button>
+              <button
+                onClick={handleImportPreview}
+                disabled={!importFile || importLoading}
+                className='px-4 py-2 text-sm font-semibold text-white bg-gray-600 rounded-lg hover:bg-gray-700 disabled:opacity-50'
+              >
+                {importLoading && !importPreview ? 'Prüfe…' : 'Vorschau prüfen'}
+              </button>
+              {importPreview && importPreview.errors === 0 && !importSuccess && (
+                <button
+                  onClick={handleImportApply}
+                  disabled={importLoading}
+                  className='px-4 py-2 text-sm font-semibold text-white bg-green-600 rounded-lg hover:bg-green-700 disabled:opacity-50'
+                >
+                  {importLoading ? 'Importiere…' : `${importPreview.created + importPreview.reactivated} Benutzer importieren`}
+                </button>
+              )}
+            </div>
+          </div>
+        </Modal>
+      )}
+
       {/* Edit User Modal */}
       {editUser && (
         <Modal title={`Mitarbeiter bearbeiten – ${editUser.full_name}`} onClose={() => setEditUser(null)}>