build(app): the editor from its hosted fork

The app took the editor from our fork of AppFlowy Editor in a folder next to the
repository, which nobody else had, and which CI can't reach either. The fork now lives at
https://code.halkyon.app/project-halkyon/appflowy-editor (public; dual-licensed AGPL-3.0
or MPL-2.0 like upstream), on its branch halkyon/win32-v6, and the app depends on it by
git URL, pinned to the signed commit 0dac8a0. That commit adds `publish_to: none` to the
fork: it is a git dependency only, and the package name belongs to AppFlowy on pub.dev.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/pubspec.yaml

@@ -25,9 +25,11 @@ resolution: workspace
 
 dependencies:
   # Our fork of the editor's main branch, moved to win32 v6 so the app can stay in the pub
-  # workspace. A local path until the fork is hosted; then a git URL pinned to a commit.
+  # workspace, pinned to a signed commit of its branch halkyon/win32-v6.
   appflowy_editor:
-    path: ../../appflowy-editor
+    git:
+      url: https://code.halkyon.app/project-halkyon/appflowy-editor.git
+      ref: 0dac8a046e91ac89c0ffa13e2d603ebf50873332
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
   clock: ^1.1.3