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>

apps/desktop/windows/CMakeLists.txt

@@ -1,10 +1,10 @@
 # Project-level configuration.
 cmake_minimum_required(VERSION 3.14)
-project(watch_together LANGUAGES CXX)
+project(starsync LANGUAGES CXX)
 
 # The name of the executable created for the application. Change this to change
 # the on-disk name of your application.
-set(BINARY_NAME "watch_together")
+set(BINARY_NAME "starsync")
 
 # Explicitly opt in to modern CMake behaviors to avoid warnings with recent
 # versions of CMake.

apps/desktop/windows/runner/Runner.rc

@@ -89,13 +89,13 @@ BEGIN
     BEGIN
         BLOCK "040904e4"
         BEGIN
-            VALUE "CompanyName", "com.example" "\0"
-            VALUE "FileDescription", "watch_together" "\0"
+            VALUE "CompanyName", "foxyz" "\0"
+            VALUE "FileDescription", "Starsync" "\0"
             VALUE "FileVersion", VERSION_AS_STRING "\0"
-            VALUE "InternalName", "watch_together" "\0"
-            VALUE "LegalCopyright", "Copyright (C) 2026 com.example. All rights reserved." "\0"
-            VALUE "OriginalFilename", "watch_together.exe" "\0"
-            VALUE "ProductName", "watch_together" "\0"
+            VALUE "InternalName", "Starsync" "\0"
+            VALUE "LegalCopyright", "Copyright (C) 2026 foxyz. All rights reserved." "\0"
+            VALUE "OriginalFilename", "starsync.exe" "\0"
+            VALUE "ProductName", "Starsync" "\0"
             VALUE "ProductVersion", VERSION_AS_STRING "\0"
         END
     END

apps/desktop/windows/runner/win32_window.cpp

@@ -16,7 +16,7 @@ namespace {
 #define DWMWA_USE_IMMERSIVE_DARK_MODE 20
 #endif
 
-constexpr const wchar_t kWindowClassName[] = L"FLUTTER_RUNNER_WIN32_WINDOW";
+constexpr const wchar_t kWindowClassName[] = L"STARSYNC_WINDOW";
 
 /// Registry key for app theme preference.
 ///