Add java/target/ to .gitignore

Ignore Maven build output directory for the Java implementation.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: konard

.gitignore

@@ -337,3 +337,6 @@ rust/target/
 target/venv/
 .venv/
 venv/
+
+# java
+java/target/