Restructure step R: the app is Starsync (dev.foxyz.starsync)

- Linux app id dev.foxyz.starsync, binary starsync; Windows starsync.exe,
  company foxyz; server starsync-server; Dart package starsync; archives
  starsync-<ver>-*.
- 1.2.x compatibility: watch_together and watch-together-server
  launchers (Linux) / copies (Windows) in the archive; the updater
  accepts both names and relaunches the new binary; update.sh/.bat use
  whichever server exists.
- First start copies (never moves) the old support folder and this
  app's Hive boxes out of ~/Documents into <support>/hive; a marker
  makes it run once; AppDirs is a port; settings schema version with
  ordered migrations.
- Launcher entry dev.foxyz.starsync.desktop; the old one removed.
- Repository name and URLs unchanged.

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

tool/release_publish.dart

@@ -45,7 +45,7 @@ Future<void> main(List<String> args) async {
   final prev = _git(root, ['describe', '--tags', '--abbrev=0', '$tag^'],
       allowFail: true);
   final notes = prev.isEmpty
-      ? 'Watch together $ver.'
+      ? 'Starsync $ver.'
       : _git(root, [
           'log',
           '$prev..$tag',
@@ -63,7 +63,7 @@ Future<void> main(List<String> args) async {
       rel = await c.post('$api/releases', {
         'tag_name': tag,
         'name': tag,
-        'body': 'Watch together $ver\n\n$notes',
+        'body': 'Starsync $ver\n\n$notes',
         'draft': false,
         'prerelease': false,
       });