Initial commit: TS3J TeamSpeak 3 Java client

Swing desktop client (core/desktop/swing Maven modules) built on the
ts3j protocol library, included as a submodule. Native Opus voice with
voice-activation detection, push-to-talk, and audio pre-processing.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "ts3j"]
+	path = ts3j
+	url = https://github.com/Manevolent/ts3j