feat: add HelpText model, service, and controller for dynamic help text management

flutter/lib/core/api/api_paths.dart

@@ -38,6 +38,10 @@ class ReceiptImportApiPaths {
   static const unitMappings = '/receipt-import/unit-mappings';
 }
 
+class HelpTextApiPaths {
+  static String byKey(String key) => '/help-texts/${Uri.encodeComponent(key)}';
+}
+
 class ReceiptAliasApiPaths {
   static const list = '/receipt-aliases';
   static String update(int id) => '/receipt-aliases/$id';

flutter/lib/features/import/data/import_repository.dart

@@ -7,6 +7,7 @@ import 'dart:developer' as developer;
 
 import '../../../core/api/api_paths.dart';
 import '../../../core/api/api_exception.dart';
+import '../domain/help_text_content.dart';
 import '../domain/quick_import_result.dart';
 
 /// Handles communication with the quick-import API endpoint.
@@ -25,6 +26,38 @@ class ImportRepository {
           defaultValue: '/api',
         );
 
+  Future<HelpTextContent> fetchHelpTextByKey(
+    String key, {
+    String? token,
+  }) async {
+    final uri = Uri.parse('$_baseUrl${HelpTextApiPaths.byKey(key)}');
+    final response = await _client.get(
+      uri,
+      headers: {
+        'Content-Type': 'application/json',
+        if (token != null) 'Authorization': 'Bearer $token',
+      },
+    );
+
+    if (response.statusCode < 200 || response.statusCode >= 300) {
+      throw ApiException(
+        type: _mapStatusCodeToErrorType(response.statusCode),
+        message: 'Kunde inte hämta hjälptext: ${response.body}',
+        statusCode: response.statusCode,
+      );
+    }
+
+    final parsed = _parseResponse(response);
+    if (parsed is! Map<String, dynamic>) {
+      throw ApiException(
+        type: ApiErrorType.unknown,
+        message: 'Felaktigt svar vid hämtning av hjälptext.',
+      );
+    }
+
+    return HelpTextContent.fromJson(parsed);
+  }
+
   /// Upload a receipt file for parsing (Fas 6b).
   /// Returns a list of parsed receipt items.
   Future<List<ParsedReceiptItem>> importReceiptFile({

flutter/lib/features/import/domain/help_text_content.dart

@@ -0,0 +1,27 @@
+class HelpTextContent {
+  final String key;
+  final String scope;
+  final String title;
+  final String content;
+  final DateTime? updatedAt;
+
+  const HelpTextContent({
+    required this.key,
+    required this.scope,
+    required this.title,
+    required this.content,
+    this.updatedAt,
+  });
+
+  factory HelpTextContent.fromJson(Map<String, dynamic> json) {
+    return HelpTextContent(
+      key: (json['key'] as String? ?? '').trim(),
+      scope: (json['scope'] as String? ?? 'default').trim(),
+      title: (json['title'] as String? ?? '').trim(),
+      content: (json['content'] as String? ?? '').trim(),
+      updatedAt: json['updatedAt'] is String
+          ? DateTime.tryParse(json['updatedAt'] as String)
+          : null,
+    );
+  }
+}

flutter/lib/features/import/presentation/receipt_import_tab.dart

@@ -14,6 +14,7 @@ import '../../pantry/data/pantry_providers.dart';
 import '../../pantry/domain/pantry_item.dart';
 import '../data/import_providers.dart';
 import '../data/receipt_import_session.dart';
+import '../domain/help_text_content.dart';
 import '../domain/parsed_receipt_item.dart';
 import '../../../core/ui/product_picker_field.dart' show ProductOption;
 import '../utils/receipt_import_utils.dart';
@@ -37,6 +38,7 @@ class ReceiptImportTab extends ConsumerStatefulWidget {
 class _ReceiptImportTabState extends ConsumerState<ReceiptImportTab> {
   bool _isLoading = false;
   bool _isSaving = false;
+  bool _isHelpLoading = false;
   PlatformFile? _pickedFile;
   bool _categoryLoadFailed = false;
   bool _globalProductsLoadFailed = false;
@@ -460,6 +462,64 @@ class _ReceiptImportTabState extends ConsumerState<ReceiptImportTab> {
     );
   }
 
+  Future<void> _showHelpForReceiptImport() async {
+    if (_isHelpLoading) return;
+    setState(() => _isHelpLoading = true);
+    try {
+      final token = await ref.read(authStateProvider.future);
+      final repo = ref.read(importRepositoryProvider);
+      final help = await repo.fetchHelpTextByKey('receipt_import', token: token);
+      if (!mounted) return;
+      await _showHelpDialog(help);
+    } catch (e) {
+      if (!mounted) return;
+      showGlobalErrorDialog(context, 'Kunde inte läsa hjälptexten just nu: $e');
+    } finally {
+      if (mounted) setState(() => _isHelpLoading = false);
+    }
+  }
+
+  Future<void> _showHelpDialog(HelpTextContent help) {
+    final updatedAt = help.updatedAt;
+    final updatedAtText = updatedAt == null
+        ? null
+        : '${updatedAt.year.toString().padLeft(4, '0')}-${updatedAt.month.toString().padLeft(2, '0')}-${updatedAt.day.toString().padLeft(2, '0')}';
+
+    return showDialog<void>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: Text(help.title.isEmpty ? 'Hjälp: Kvittoimport' : help.title),
+        content: SizedBox(
+          width: 560,
+          child: SingleChildScrollView(
+            child: Column(
+              crossAxisAlignment: CrossAxisAlignment.start,
+              mainAxisSize: MainAxisSize.min,
+              children: [
+                SelectableText(help.content),
+                const SizedBox(height: 12),
+                Wrap(
+                  spacing: 8,
+                  runSpacing: 8,
+                  children: [
+                    Chip(label: Text('Scope: ${help.scope}')),
+                    if (updatedAtText != null) Chip(label: Text('Uppdaterad: $updatedAtText')),
+                  ],
+                ),
+              ],
+            ),
+          ),
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.of(ctx).pop(),
+            child: const Text('Stäng'),
+          ),
+        ],
+      ),
+    );
+  }
+
   void _deleteItem(int index) {
     final items = _items;
     if (items == null || index < 0 || index >= items.length) return;
@@ -819,9 +879,28 @@ class _ReceiptImportTabState extends ConsumerState<ReceiptImportTab> {
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [
-          Text(
-            'Ladda upp ett kvitto (PDF eller bild) — raderna tolkas och kan läggas till i ditt inventarie.',
-            style: theme.textTheme.bodyMedium?.copyWith(color: theme.colorScheme.onSurfaceVariant),
+          Row(
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              Expanded(
+                child: Text(
+                  'Ladda upp ett kvitto (PDF eller bild) — raderna tolkas och kan läggas till i ditt inventarie.',
+                  style: theme.textTheme.bodyMedium?.copyWith(color: theme.colorScheme.onSurfaceVariant),
+                ),
+              ),
+              const SizedBox(width: 8),
+              TextButton.icon(
+                onPressed: _isHelpLoading ? null : _showHelpForReceiptImport,
+                icon: _isHelpLoading
+                    ? const SizedBox(
+                        width: 14,
+                        height: 14,
+                        child: CircularProgressIndicator(strokeWidth: 2),
+                      )
+                    : const Icon(Icons.help_outline),
+                label: const Text('Läs hjälp'),
+              ),
+            ],
           ),
           const SizedBox(height: 20),
           OutlinedButton.icon(