Guard spdlog async bench recorder lifetime and add ASAN check

[LimiNode]

Summary

• coordinate LatencyRecorder completion with wait/notify and shared handles held by adapters
• rework spdlog measuring sink to own payloads, finish pending tokens, and protect recorder lifetime
• add ASAN benchmark job that runs the spdlog async null scenario with sanitizers enabled

Testing

• not run (local build interrupted by warnings)

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Codex Task