Add test module for rsip wrapper

[altanai]

New C wrapper test module and related wiring to improve the rsip-wrapper testing surface and CI coverage

• updates the mod_rsip_example and rsip-wrapper test integration (C sources and header in include and mod_rsip_example/).
• Adds/updates Rust FFI glue in lib.rs and associated C examples/tests (mod_rsip.c, test_mod_rsip.c) to exercise the wrapper.
• Adjusts build/test metadata to ensure the wrapper builds and the integration tests run under CI.
• Miscellaneous small fixes to support the new tests (tokenizers, header handling, and test utilities).