build(train): serverpod start leaves the app to be run on a device

Serverpod's default device for a companion app is the web server, which
Train doesn't build for, so the launch failed. The app is run by hand on
the emulator or a phone with `flutter run -d <device> -t lib/driver.dart`.

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/train/halkyon_train_server/pubspec.yaml

@@ -47,5 +47,9 @@ serverpod:
     halkyon_train:
       path: ../halkyon_train_flutter
       displayName: "Halkyon Train"
-      auto_launch: true
+      # Not launched with the server: its default device is the web server,
+      # which Train doesn't build for, and most of Train is Android's. Run it
+      # on a device with `flutter run -d <device> -t lib/driver.dart` from
+      # its folder.
+      auto_launch: false
       target: lib/driver.dart