Never publish this fork

Halkyon Learn uses this fork as a git dependency, from
https://code.halkyon.app/project-halkyon/appflowy-editor. The package name
appflowy_editor belongs to AppFlowy on pub.dev, so `dart pub publish` should refuse
outright rather than depend on pub.dev refusing the upload.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pubspec.yaml

@@ -2,6 +2,10 @@ name: "appflowy_editor"
 
 version: 6.1.0
 
+# Halkyon Learn's fork (https://code.halkyon.app/project-halkyon/appflowy-editor), used
+# as a git dependency. Never published: the package name belongs to AppFlowy on pub.dev.
+publish_to: none
+
 homepage: "https://github.com/AppFlowy-IO/appflowy-editor"
 
 environment: