Feature 18371
- Add build.gradle.glibc25 for GLIBC 2.5 compatible builds
- Add cellframe_jni_glibc25.c with complete JNI implementation (23 functions)
- Update Dockerfile.glibc25 for reproducible builds
- Supports CentOS 5+, Ubuntu 6.06+, RHEL 5+ (21+ years compatibility)
- Original build.gradle.kts unchanged