fix: update free text validation regex handling

app/lib/l10n/app_de.arb

@@ -246,14 +246,7 @@
   },
   "free_text_alphanumeric_error": "Bitte geben Sie nur alphanumerische Zeichen ein",
   "free_text_numeric_error": "Bitte geben Sie nur numerische Zeichen ein",
-  "free_text_custom_error": "Bitte geben Sie nur Zeichen ein, die dem Muster {pattern} entsprechen",
-  "@free_text_custom_error": {
-    "placeholders": {
-      "pattern": {
-        "type": "String"
-      }
-    }
-  },
+  "free_text_custom_error": "Bitte geben Sie einen Wert im erforderlichen Format ein",
   "app_outdated_message": "Eine neue Version der StudyU App ist verfügbar. Bitte führen Sie eine Aktualisierung durch, um die neuesten Funktionen und Verbesserungen zu erhalten. Vielen Dank für Ihre Unterstützung!",
   "update_now": "Jetzt aktualisieren",
 

app/lib/l10n/app_en.arb

@@ -242,14 +242,7 @@
   },
   "free_text_alphanumeric_error": "Please enter only alphanumeric characters",
   "free_text_numeric_error": "Please enter only numeric characters",
-  "free_text_custom_error": "Please enter only characters matching the pattern {pattern}",
-  "@free_text_custom_error": {
-    "placeholders": {
-      "pattern": {
-        "type": "String"
-      }
-    }
-  },
+  "free_text_custom_error": "Please enter a value in the required format",
   "app_outdated_message": "A new version of the StudyU App is available. Please update to get the latest features and improvements. Thank you for your support!",
   "update_now": "Update now",
 

app/lib/l10n/app_localizations.dart

@@ -1235,8 +1235,8 @@ abstract class AppLocalizations {
   /// No description provided for @free_text_custom_error.
   ///
   /// In en, this message translates to:
-  /// **'Please enter only characters matching the pattern {pattern}'**
-  String free_text_custom_error(String pattern);
+  /// **'Please enter a value in the required format'**
+  String get free_text_custom_error;
 
   /// No description provided for @app_outdated_message.
   ///

app/lib/l10n/app_localizations_de.dart

@@ -1,6 +1,5 @@
 // ignore: unused_import
 import 'package:intl/intl.dart' as intl;
-
 import 'app_localizations.dart';
 
 // ignore_for_file: type=lint
@@ -639,9 +638,8 @@ class AppLocalizationsDe extends AppLocalizations {
       'Bitte geben Sie nur numerische Zeichen ein';
 
   @override
-  String free_text_custom_error(String pattern) {
-    return 'Bitte geben Sie nur Zeichen ein, die dem Muster $pattern entsprechen';
-  }
+  String get free_text_custom_error =>
+      'Bitte geben Sie einen Wert im erforderlichen Format ein';
 
   @override
   String get app_outdated_message =>

app/lib/l10n/app_localizations_en.dart

@@ -1,6 +1,5 @@
 // ignore: unused_import
 import 'package:intl/intl.dart' as intl;
-
 import 'app_localizations.dart';
 
 // ignore_for_file: type=lint
@@ -632,9 +631,8 @@ class AppLocalizationsEn extends AppLocalizations {
   String get free_text_numeric_error => 'Please enter only numeric characters';
 
   @override
-  String free_text_custom_error(String pattern) {
-    return 'Please enter only characters matching the pattern $pattern';
-  }
+  String get free_text_custom_error =>
+      'Please enter a value in the required format';
 
   @override
   String get app_outdated_message =>

app/lib/widgets/questionnaire/question_container.dart

@@ -16,13 +16,15 @@ import 'package:studyu_core/core.dart';
 
 class QuestionContainer extends StatefulWidget {
   final Function(Answer, int) onDone;
+  final Function(int)? onInvalid;
   final Question question;
   final int index;
   final String? taskId;
   final GlobalKey? containerKey;
 
   const QuestionContainer({
     required this.onDone,
+    this.onInvalid,
     required this.question,
     required this.index,
     this.taskId,
@@ -40,6 +42,10 @@ class _QuestionContainerState extends State<QuestionContainer>
     widget.onDone(answer, widget.index);
   }
 
+  void _onInvalid() {
+    widget.onInvalid?.call(widget.index);
+  }
+
   QuestionWidget getQuestionBody(BuildContext context) {
     switch (widget.question) {
       case final ChoiceQuestion choiceQuestion:
@@ -83,6 +89,7 @@ class _QuestionContainerState extends State<QuestionContainer>
         return FreeTextQuestionWidget(
           question: freeTextQuestion,
           onDone: _onDone,
+          onInvalid: _onInvalid,
         );
       case final FitbitQuestion fitbitQuestion:
         return FitbitQuestionWidget(

app/lib/widgets/questionnaire/questionnaire_widget.dart

@@ -55,6 +55,7 @@ class _QuestionnaireWidgetState extends State<QuestionnaireWidget> {
         containerKey: containerKey,
         question: question,
         onDone: _onQuestionDone,
+        onInvalid: _onQuestionInvalid,
         index: shownQuestions.length,
         taskId: widget.taskId,
       ),
@@ -140,6 +141,12 @@ class _QuestionnaireWidgetState extends State<QuestionnaireWidget> {
     }
   }
 
+  void _onQuestionInvalid(int index) {
+    final questionId = shownQuestions[index].question.id;
+    qs.answers.remove(questionId);
+    _finishQuestionnaire(null);
+  }
+
   void _onQuestionDone(Answer answer, int index) {
     if (kDebugMode) {
       debugPrint(
@@ -149,12 +156,6 @@ class _QuestionnaireWidgetState extends State<QuestionnaireWidget> {
     qs.answers[answer.question] = answer;
     final shouldContinue = widget.shouldContinue?.call(qs);
 
-    // Check if the questionnaire should not continue
-    if (shouldContinue == false) {
-      _finishQuestionnaire(qs);
-      return;
-    }
-
     // Check if there are questions whose visibility depend on this question
     final hasConditionalDependencies = _isConditionalTarget(answer.question);