feat: QR-Login mit der Employee-App

Neuer 4. Login-Modus "QR" im LoginScreen: scannt den Token, den die
Employee-App unter "Am Kiosk anmelden" anzeigt (POST /kiosk/my-qr-token im
Haupt-Repo), meldet den Mitarbeiter per POST /kiosk/auth/qr an. Eigener
QrLoginScanScreen (rohe Token-String statt JSON wie beim Geräte-Enrollment-
QR). v0.1.11+12.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Dzdm3EWeNdYFUuXFRJryA1

lib/app_version.dart

@@ -1,3 +1,3 @@
 /// Manuell mit pubspec.yaml synchron halten (siehe timemaster-mobile,
 /// gleiche Konvention – kein package_info_plus während aktiver Feldtests).
-const String kAppVersion = '0.1.10+11';
+const String kAppVersion = '0.1.11+12';

lib/screens/login_screen.dart

@@ -9,9 +9,10 @@ import '../services/api_client.dart';
 import '../services/kiosk_service.dart';
 import '../services/update_check_service.dart';
 import 'enrollment_screen.dart';
+import 'qr_login_scan_screen.dart';
 import 'stamp_screen.dart';
 
-enum _LoginMode { pin, nfc, list }
+enum _LoginMode { pin, nfc, list, qr }
 
 class LoginScreen extends StatefulWidget {
   const LoginScreen({super.key});
@@ -350,6 +351,7 @@ class _LoginScreenState extends State<LoginScreen> {
                     ButtonSegment(value: _LoginMode.pin, label: Text('PIN'), icon: Icon(Icons.pin)),
                     ButtonSegment(value: _LoginMode.nfc, label: Text('NFC'), icon: Icon(Icons.nfc)),
                     ButtonSegment(value: _LoginMode.list, label: Text('Liste'), icon: Icon(Icons.people)),
+                    ButtonSegment(value: _LoginMode.qr, label: Text('QR'), icon: Icon(Icons.qr_code_scanner)),
                   ],
                   selected: {_mode},
                   onSelectionChanged: (s) {
@@ -373,6 +375,7 @@ class _LoginScreenState extends State<LoginScreen> {
                 if (_mode == _LoginMode.pin) ..._pinForm(),
                 if (_mode == _LoginMode.nfc) ..._nfcForm(),
                 if (_mode == _LoginMode.list) ..._listForm(),
+                if (_mode == _LoginMode.qr) ..._qrForm(),
                 if (_error != null) ...[
                   const SizedBox(height: 16),
                   Text(_error!, style: const TextStyle(color: Colors.red), textAlign: TextAlign.center),
@@ -479,4 +482,44 @@ class _LoginScreenState extends State<LoginScreen> {
       ),
     ];
   }
+
+  Future<void> _scanAndLoginQr() async {
+    final token = await Navigator.of(context).push<String>(
+      MaterialPageRoute(builder: (_) => const QrLoginScanScreen()),
+    );
+    if (token == null || !mounted) return;
+    setState(() {
+      _loading = true;
+      _error = null;
+    });
+    try {
+      final session = await _service.loginQr(token);
+      if (!mounted) return;
+      _goToStamp(session);
+    } on DioException catch (e) {
+      setState(() => _error = _dioMessage(e));
+    } catch (_) {
+      if (mounted) setState(() => _error = 'Unerwartete Antwort vom Server.');
+    } finally {
+      if (mounted) setState(() => _loading = false);
+    }
+  }
+
+  List<Widget> _qrForm() {
+    return [
+      const Icon(Icons.qr_code_2, size: 80, color: Colors.indigo),
+      const SizedBox(height: 16),
+      const Text('QR-Code aus der TimeMaster-App scannen ("Am Kiosk anmelden").'),
+      const SizedBox(height: 24),
+      SizedBox(
+        width: double.infinity,
+        height: 56,
+        child: FilledButton.icon(
+          onPressed: _loading ? null : _scanAndLoginQr,
+          icon: const Icon(Icons.qr_code_scanner),
+          label: _loading ? const Text('Prüfe…') : const Text('QR-Code scannen'),
+        ),
+      ),
+    ];
+  }
 }

lib/screens/qr_login_scan_screen.dart

@@ -0,0 +1,76 @@
+import 'package:flutter/material.dart';
+import 'package:mobile_scanner/mobile_scanner.dart';
+
+/// Scannt den QR-Login-Code aus der Employee-App (POST /kiosk/my-qr-token).
+/// Inhalt ist der rohe Token-String (kein JSON, anders als beim Geräte-
+/// Enrollment-QR in qr_enrollment_scan_screen.dart).
+class QrLoginScanScreen extends StatefulWidget {
+  const QrLoginScanScreen({super.key});
+
+  @override
+  State<QrLoginScanScreen> createState() => _QrLoginScanScreenState();
+}
+
+class _QrLoginScanScreenState extends State<QrLoginScanScreen> {
+  // Gleiche feste Auflösung wie beim Enrollment-Scan – siehe dortiger
+  // Kommentar (R8/ProGuard war die eigentliche Ursache für Scan-Abstürze,
+  // die feste Auflösung bleibt trotzdem als sinnvolle Optimierung).
+  MobileScannerController _buildController() => MobileScannerController(
+        formats: const [BarcodeFormat.qrCode],
+        cameraResolution: const Size(1280, 720),
+      );
+
+  late MobileScannerController _controller = _buildController();
+  bool _handled = false;
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  void _onDetect(BarcodeCapture capture) {
+    if (_handled) return;
+    final raw = capture.barcodes.firstOrNull?.rawValue;
+    if (raw == null || raw.isEmpty) return;
+    _handled = true;
+    Navigator.of(context).pop(raw);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('QR-Login scannen')),
+      body: MobileScanner(
+        controller: _controller,
+        onDetect: _onDetect,
+        errorBuilder: (context, error, child) {
+          return Container(
+            color: Colors.black,
+            padding: const EdgeInsets.all(24),
+            child: Center(
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
+                children: [
+                  const Icon(Icons.error_outline, color: Colors.red, size: 48),
+                  const SizedBox(height: 16),
+                  Text('Kamera-Fehler: ${error.errorCode}',
+                      style: const TextStyle(color: Colors.white, fontWeight: FontWeight.bold)),
+                  const SizedBox(height: 24),
+                  OutlinedButton(
+                    onPressed: () => Navigator.of(context).pop(),
+                    child: const Text('Zurück', style: TextStyle(color: Colors.white)),
+                  ),
+                ],
+              ),
+            ),
+          );
+        },
+      ),
+    );
+  }
+}
+
+extension _FirstOrNull<T> on List<T> {
+  T? get firstOrNull => isEmpty ? null : first;
+}

lib/services/kiosk_service.dart

@@ -24,6 +24,11 @@ class KioskService {
     return KioskSession.fromJson(r.data as Map<String, dynamic>);
   }
 
+  Future<KioskSession> loginQr(String qrToken) async {
+    final r = await _dio.post('/kiosk/auth/qr', data: {'qr_token': qrToken});
+    return KioskSession.fromJson(r.data as Map<String, dynamic>);
+  }
+
   Future<KioskSession> loginList(String userId) async {
     final r = await _dio.post('/kiosk/auth/list', data: {'user_id': userId});
     return KioskSession.fromJson(r.data as Map<String, dynamic>);

pubspec.yaml

@@ -1,7 +1,7 @@
 name: timemaster_kiosk
 description: TimeMaster Kiosk – Stempeluhr für Android-Tablets hinter VPN
 publish_to: 'none'
-version: 0.1.10+11
+version: 0.1.11+12
 
 environment:
   sdk: '>=3.3.0 <4.0.0'