Convert desktop to EchoType Bridge: pipe injection via TIP

- Add EchoType to TextInjectionMode enum (becomes default)
- Add WriteToEchoTypePipe(): write [UINT32 cch][WCHAR text] to
  \.\pipe\EchoType\pid_<PID> via NamedPipeClientStream
- InsertText(): route to EchoType pipe when mode is EchoType
- TrayApplicationContext: add 'EchoType (recommended)' to input mode menu
- Update tray branding: 'EchoType Bridge' in tooltips and balloon tips
- AppLogger: log to %LocalAppData%\EchoType\bridge.log

The bridge keeps WebSocket server + UDP discovery + audio control
unchanged. Text injection now goes through the EchoType TIP's
composition-commit mechanism for atomic insertion, falling back to
clipboard and SendInput as secondary options.

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

WirelessTextSyncer.Windows/Services/AppLogger.cs

@@ -5,9 +5,9 @@ public static class AppLogger
     private static readonly object SyncRoot = new();
     private static readonly string LogDirectory = Path.Combine(
         Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
-        "WirelessTextSyncer");
+        "EchoType");
 
-    public static string LogPath => Path.Combine(LogDirectory, "desktop.log");
+    public static string LogPath => Path.Combine(LogDirectory, "bridge.log");
 
     public static void Info(string message)
     {