refactor(runtime): use OpenTelemetry trace propagation

[PeaBrane]

Summary

• replace duplicated manual W3C trace-context parsing across HTTP, NATS, and TCP with OpenTelemetry propagation
• centralize carrier extraction behind a thin GenericHeaderExtractor while retaining exact W3C trace/span ID field-width checks
• preserve raw tracestate, request-ID behavior, trace flags, and existing public helper signatures
• remove 106 net lines without adding a dependency

Validation

• focused existing runtime tests for valid/malformed traceparent parsing, unsampled propagation, header injection, inbound request spans, distributed context, and sampled/unsampled root decisions (8 passed)
• cargo fmt --all -- --check
• git diff --check main..HEAD
• release B/C frontend benchmark against mock workers with W3C trace headers, 8,192 measured requests per trial, zero errors:
  • concurrency 256, three paired trials: frontend CPU/request -0.19%, throughput +0.05%
  • concurrency 1024, five paired trials: frontend CPU/request +0.89%, throughput -1.41%, mean latency +1.89%, p95 -0.58%, p99 -3.80%

The stressed-point movement is minor and mixed rather than a material regression. Every trial used a fresh frontend/mocker topology, separate warmup, identical JSONL tracing, and disjoint CPU placement.

Summary by CodeRabbit

• New Features

  • Improved distributed tracing across HTTP, NATS, and other supported request headers.
  • Trace context and request identifiers are now preserved more consistently.
  • Added support for tracing headers from newer trace versions.

• Bug Fixes

  • Improved validation and normalization of tracing metadata.
  • Standardized trace extraction behavior across supported transports.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between dbecec8 and fe98f90.

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• lib/runtime/src/logging.rs

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Walkthrough

Traceparent parsing now uses a shared OpenTelemetry propagator for multiple header formats. The shared extractor returns trace metadata, tracestate, request identifiers, and optional OTel context. Request and payload span constructors use this extraction path.

Changes

Trace context extraction

Layer / File(s)	Summary
Shared propagator extraction lib/runtime/src/logging.rs	parse_traceparent and TraceParent::from_headers use generic headers and shared OpenTelemetry extraction. The extractor validates field widths and preserves trace metadata, tracestate, and request identifiers.
Span constructor integration lib/runtime/src/logging.rs	Inference, system, NATS, TCP, and HashMap span constructors consume the shared extraction result and OTel context.
Parser behavior validation lib/runtime/src/logging.rs	Tests cover normalized flags, future traceparent versions, and clearing unsupported flag bits.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Merge Risk: ⚪ Minimal · up to fe98f

This PR centralizes trace propagation without changing the documented behavior, and its focused validation shows no material performance regression; no actionable merge-blocking risk remains after normal checks and review.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description explains the changes and validation, but it omits the required Related Issues section from the repository template.	Add the required Related Issues section and either link the relevant issue or confirm that this PR has no related issue.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main change to use OpenTelemetry trace propagation in the runtime.
Docstring Coverage	✅ Passed	Docstring check was indeterminate for this PR — some files could not be analyzed in time. Not blocking.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches 💡 1

🛠️ Fix failing CI checks 💡

• Create stacked PR
• Commit on current branch

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.