chore: flutter_markdown (eingestellt) -> flutter_markdown_plus

Gleiche API, gepflegter Nachfolger. Rendertest für die Markdown-Vorschau
(test/document_markdown_test.dart).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

lib/features/chat/document_viewer.dart

@@ -6,7 +6,7 @@ import 'package:archive/archive.dart';
 import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
-import 'package:flutter_markdown/flutter_markdown.dart';
+import 'package:flutter_markdown_plus/flutter_markdown_plus.dart';
 import 'package:flutter_svg/flutter_svg.dart';
 import 'package:path_provider/path_provider.dart';
 import 'package:pdfx/pdfx.dart';

pubspec.lock

@@ -400,14 +400,14 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
-  flutter_markdown:
+  flutter_markdown_plus:
     dependency: "direct main"
     description:
-      name: flutter_markdown
-      sha256: "08fb8315236099ff8e90cb87bb2b935e0a724a3af1623000a9cec930468e0f27"
+      name: flutter_markdown_plus
+      sha256: fce641d6c2106cc495de1cd603f97a4f9d615a97a64011928ded380dbdade935
       url: "https://pub.dev"
     source: hosted
-    version: "0.7.7+1"
+    version: "1.0.12"
   flutter_plugin_android_lifecycle:
     dependency: transitive
     description:

pubspec.yaml

@@ -67,7 +67,7 @@ dependencies:
   # Document viewer
   pdfx: ^2.7.0
   archive: ^4.0.0
-  flutter_markdown: ^0.7.7
+  flutter_markdown_plus: ^1.0.3
 
   # Clipboard image paste (Windows FFI) & image decoding
   ffi: ^2.1.0

test/document_markdown_test.dart

@@ -0,0 +1,42 @@
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pyramid/core/theme.dart';
+import 'package:pyramid/features/chat/document_viewer.dart';
+
+/// Markdown-Vorschau (seit 2026-10-07 mit flutter_markdown_plus statt dem
+/// eingestellten flutter_markdown): Überschrift, Liste, Code und Link werden
+/// gezeichnet.
+void main() {
+  testWidgets('Markdown-Datei wird in der Vorschau dargestellt', (
+    tester,
+  ) async {
+    const md = '# Einkaufsliste\n\n'
+        '- **Milch**\n- _Brot_\n\n'
+        '`code` und [ein Link](https://example.org)\n\n'
+        '> Zitat\n';
+    await tester.pumpWidget(
+      PyramidTheme(
+        child: MaterialApp(
+          home: DocumentViewer(
+            filename: 'notizen.md',
+            bytes: Uint8List.fromList(utf8.encode(md)),
+            senderName: 'Test',
+          ),
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    expect(tester.takeException(), isNull);
+    // Auswählbarer Text (SelectableText → EditableText) oder RichText.
+    bool shows(String text) =>
+        find.textContaining(text, findRichText: true).evaluate().isNotEmpty;
+    expect(shows('Einkaufsliste'), isTrue);
+    expect(shows('Milch'), isTrue);
+    expect(shows('ein Link'), isTrue);
+    expect(shows('Zitat'), isTrue);
+  });
+}