Bring Java bindings up to C API parity

[adsharma]

Summary

Bring the Java bindings closer to the current C API and Go cgo binding surface:

• add extended database system configuration fields
• add read-only prepared statement inspection
• add recursive relationship list accessors
• add Arrow table registration, CSR relationship registration, drop-table, and query-result chunk export APIs through Apache Arrow Java C Data Interface
• add CI that fetches published Java native-library artifacts before running Gradle checks

Notes

lbugDatabaseInitExtended is intentionally temporary so this Java checkout can run against currently published native artifacts while new main-repo artifacts catch up. A TODO is included next to the native declaration to fold it back into lbugDatabaseInit after artifacts are rebuilt.

Validation

• SKIP_CMAKE_BUILD=true ./gradlew compileJava compileTestJava
• clang++ -std=c++20 -fsyntax-only ... src/jni/lbug_java.cpp
• verified download-native-libs.sh against upstream run 26604242869 on macOS arm64