feat(inference): add attributed debug logging for inference.local

[geelen]

Summary

Add opt-in attributed debug logging for inference.local requests in the sandbox proxy. Just raising this for visibility/discussion

Related Issue

Changes

From Codex:

• refactor socket-owner resolution into a reusable procfs identity snapshot
• resolve process identity before the inference.local fast path and thread it through inference handling
• add an internal append-only JSONL debug logger gated by OPENSHELL_INFERENCE_DEBUG_LOG
• capture PID, binary path, ancestor binaries, cmdline paths, request metadata, selected route/provider/model, sanitized headers, capped body snippets, response metadata, timing, and outcome
• preserve provider_type in resolved route metadata so the selected provider can be logged
• add focused tests for JSONL serialization, truncation, and log-header redaction
• document how to enable the debug log in the inference routing architecture note

Testing

Checklist

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