perf(bench): add formatted public macro scenario

[LimiNode]

Summary

• add a separate SimpleLogFormatter public LOGIT_INFO(...) benchmark alongside the passthrough record-construction scenario;
• add a versioned benchmark fixture contract and runtime metadata line for compiler/toolchain/source commit/queue/flush settings;
• run both public-macro scenarios in the Linux benchmark CI job;
• mark the benchmark follow-up complete in the roadmap while keeping production exec_mx lock-elision as a separate research item.

Verification

• local Release build passed for logit_public_macro_bench, logit_public_macro_formatted_bench, logit_hotpath_bench, logit_hotpath_bench_legacy, and logit_bench;
• local smoke passed for passthrough and formatted public macro benchmarks, hot-path A/B, and filtered latency benchmark;
• fixture JSON parses successfully;
• git diff --check passed.

This PR does not change production logger synchronization or claim universal performance gains.