Render and navigate [[wikilink]] syntax in notes

- Add WikilinkSyntax (InlineSyntax) that parses [[Note Title]] into
  anchor elements with a wikilink:// href
- wikilinkExtensionSet extends GFM with this syntax; shared by detail
  view and edit preview so rendering is consistent
- NoteDetailScreen handles onTapLink: wikilink:// hrefs look up the
  target note by title (case-insensitive) and push its detail route;
  unresolved links show a "Note not found" snackbar
- Add markdown as an explicit dependency (was previously transitive)

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

lib/core/wikilink_syntax.dart

@@ -0,0 +1,24 @@
+import 'package:markdown/markdown.dart' as md;
+
+/// Parses `[[Note Title]]` wikilinks into anchor elements with a custom
+/// `wikilink://<encoded-title>` href, handled by the app's onTapLink callback.
+class WikilinkSyntax extends md.InlineSyntax {
+  WikilinkSyntax() : super(r'\[\[([^\[\]\n]+)\]\]');
+
+  @override
+  bool onMatch(md.InlineParser parser, Match match) {
+    final title = match[1]!.trim();
+    if (title.isEmpty) return false;
+    final anchor = md.Element.text('a', title);
+    anchor.attributes['href'] = 'wikilink://${Uri.encodeComponent(title)}';
+    parser.addNode(anchor);
+    return true;
+  }
+}
+
+/// GitHub-flavored markdown extended with [[wikilink]] support.
+/// Use this as the extensionSet wherever note bodies are rendered.
+final wikilinkExtensionSet = md.ExtensionSet(
+  md.ExtensionSet.gitHubFlavored.blockSyntaxes,
+  [WikilinkSyntax(), ...md.ExtensionSet.gitHubFlavored.inlineSyntaxes],
+);

lib/screens/notes/note_detail_screen.dart

@@ -4,6 +4,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
 import '../../core/constants.dart';
+import '../../core/wikilink_syntax.dart';
 import '../../providers/notes_provider.dart';
 
 class NoteDetailScreen extends ConsumerWidget {
@@ -15,6 +16,22 @@ class NoteDetailScreen extends ConsumerWidget {
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final noteAsync = ref.watch(noteDetailProvider(noteId));
+    final allNotes = ref.watch(notesProvider).valueOrNull ?? [];
+
+    void navigateByTitle(String title) {
+      final matches = allNotes.where(
+        (n) => n.title.toLowerCase() == title.toLowerCase(),
+      );
+      if (matches.isNotEmpty) {
+        context.push(
+          Routes.noteDetail.replaceFirst(':id', '${matches.first.id}'),
+        );
+      } else {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(content: Text('Note not found: "$title"')),
+        );
+      }
+    }
 
     return Scaffold(
       appBar: AppBar(
@@ -71,6 +88,13 @@ class NoteDetailScreen extends ConsumerWidget {
         data: (note) => Markdown(
           data: note.body,
           selectable: true,
+          extensionSet: wikilinkExtensionSet,
+          onTapLink: (text, href, _) {
+            if (href == null) return;
+            if (href.startsWith('wikilink://')) {
+              navigateByTitle(Uri.decodeComponent(href.substring(11)));
+            }
+          },
         ),
       ),
     );

lib/screens/notes/note_edit_screen.dart

@@ -4,6 +4,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
 import '../../core/exceptions.dart';
+import '../../core/wikilink_syntax.dart';
 import '../../providers/api_client_provider.dart';
 import '../../providers/notes_provider.dart';
 
@@ -149,7 +150,10 @@ class _NoteEditScreenState extends ConsumerState<NoteEditScreen> {
                     const Divider(),
                     Expanded(
                       child: _preview
-                          ? Markdown(data: _contentController.text)
+                          ? Markdown(
+                              data: _contentController.text,
+                              extensionSet: wikilinkExtensionSet,
+                            )
                           : Padding(
                               padding:
                                   const EdgeInsets.symmetric(horizontal: 16),

pubspec.lock

@@ -353,7 +353,7 @@ packages:
     source: hosted
     version: "1.3.0"
   markdown:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: markdown
       sha256: "935e23e1ff3bc02d390bad4d4be001208ee92cc217cb5b5a6c19bc14aaa318c1"

pubspec.yaml

@@ -20,6 +20,7 @@ dependencies:
   path_provider: ^2.1.4
   shared_preferences: ^2.3.2
   flutter_markdown: ^0.7.3
+  markdown: ^7.2.2
   flutter_inappwebview: ^6.1.5
 
 dev_dependencies: