chore: Halkyon Todo's scaffold joins the repository in apps/todo

Its server, client and app as `serverpod create` made them, with the
switch to server-side sessions that was waiting uncommitted, as files:
its one commit holds the scaffold alone.

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

apps/todo/halkyon_todo_flutter/README.md

@@ -0,0 +1,15 @@
+# halkyon_todo_flutter
+
+A new Flutter project with Serverpod.
+
+## Getting Started
+
+This project is a starting point for a Flutter application that is using
+Serverpod.
+
+A great starting point for learning Serverpod is our documentation site at:
+[https://docs.serverpod.dev](https://docs.serverpod.dev).
+
+To run the project, first make sure that the server is running, then do:
+
+    flutter run