Update ts3j: resend like the official client; clean up failed connects

- ts3j: native resend timing, INIT1 resends, one clientinitiv per handshake,
  non-blocking disconnect.
- Ignore errors from a connect attempt that has been superseded or cancelled.
- Show the whole cause chain in network error messages.
- -Dts3j.debug=true enables ts3j's protocol logging.
- Tests run with a throwaway user.home instead of the real profile.

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

ts3-client/swing/src/main/java/com/ts3client/Main.java

@@ -15,9 +15,10 @@ import javax.swing.SwingUtilities;
 public final class Main {
 
     public static void main(String[] args) {
-        // ts3j is verbose by default; keep the console quiet unless debugging.
+        // ts3j is verbose by default; keep the console quiet unless asked for its protocol log
+        // (-Dts3j.debug=true, written to stderr).
         try {
-            com.github.manevolent.ts3j.util.Ts3Debugging.setEnabled(false);
+            com.github.manevolent.ts3j.util.Ts3Debugging.setEnabled(Boolean.getBoolean("ts3j.debug"));
         } catch (Throwable ignored) {
         }