Set version to 26.03.01.1 (YY.MM.DD.iteration format)

pubspec: 26.03.01+1 (Flutter uses + to separate versionName/versionCode)
Update checker combines version + buildNumber → "26.03.01.1" for
comparison against Forgejo release tags in the same format.

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

lib/providers/update_provider.dart

@@ -51,7 +51,9 @@ class UpdateNotifier extends Notifier<UpdateState> {
     state = state.copyWith(status: UpdateStatus.checking);
     try {
       final packageInfo = await PackageInfo.fromPlatform();
-      final currentVersion = packageInfo.version;
+      // Combine versionName + buildNumber to match the YY.MM.DD.N tag format.
+      final currentVersion =
+          '${packageInfo.version}.${packageInfo.buildNumber}';
 
       // Parse repo URL → Forgejo API endpoint
       final uri = Uri.parse(repoUrl);