Never publish this fork

Halkyon Learn uses this fork as a git dependency, from
https://code.halkyon.app/project-halkyon/serverpod-offline-sync. The package name
serverpod_offline_sync belongs to its author 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>
Claude-Session: https://claude.ai/code/session_01MMm7usAo6q9ZZRoPkWjoxi

packages/serverpod_offline_sync/pubspec.yaml

@@ -2,6 +2,10 @@ name: serverpod_offline_sync
 version: 0.0.10
 description: Shared package for the Serverpod Offline Sync project.
 homepage: https://github.com/marcelomendoncasoares/serverpod_offline_sync
+# Halkyon Learn's fork, used as a git dependency from
+# https://code.halkyon.app/project-halkyon/serverpod-offline-sync; the name
+# belongs to the package on pub.dev.
+publish_to: none
 
 environment:
   sdk: '^3.12.2'