fix: log span_id next to trace_id

[ferhatelmas]

What kind of change does this PR introduce?

Improvement for tracing logging

What is the current behavior?

#1224 added trace_id logging but it's not enough, because it doesn't know under which span to put logs.

What is the new behavior?

Similar to trace_id, log span_id as top level.

Additional context

For GC pressure, adapt get trace context to return full value and only slice for serialization without interim object.

[Copilot]

Pull request overview

This PR improves tracing-related structured logging by promoting the W3C traceparent span identifier alongside the existing trace_id, and refactors traceparent parsing to reduce intermediate allocations.

Changes:

• Refactor traceparent helper to return the validated full traceparent value (instead of slicing out only the trace id).
• Add spanId to request log context and promote it to Logflare as top-level span_id.
• Update request logging + Logflare + helper unit tests to cover spanId behavior.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/internal/monitoring/request-context.ts	Rename/refactor traceparent helper to return validated traceparent string.
src/internal/monitoring/request-context.test.ts	Update unit tests for the new traceparent helper behavior.
src/internal/monitoring/logger.ts	Extend RequestLog type to include spanId.
src/internal/monitoring/logflare.ts	Promote spanId to top-level span_id in Logflare payload preparation.
src/internal/monitoring/logflare.test.ts	Update Logflare payload tests to include span_id.
src/http/plugins/log-request.ts	Parse span id from trace context and include it in request logs.
src/http/plugins/log-request.test.ts	Update request logging tests to validate spanId threading/empty cases.

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[coveralls]

Coverage Report for CI Build 29050683086

Coverage decreased (-0.1%) to 79.325%

Details

• Coverage decreased (-0.1%) from the base build.
• Patch coverage: 9 of 9 lines across 3 files are fully covered (100%).
• 20 coverage regressions across 3 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

20 previously-covered lines in 3 files lost coverage.

File	Lines Losing Coverage	Coverage
src/internal/http/agent.ts	17	32.56%
src/http/routes/s3/index.ts	2	82.99%
src/http/plugins/db.ts	1	81.82%

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Coverage Stats

Relevant Lines:	12633
Covered Lines:	10468
Line Coverage:	82.86%
Relevant Branches:	7323
Covered Branches:	5362
Branch Coverage:	73.22%
Branches in Coverage %:	Yes
Coverage Strength:	424.07 hits per line

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💛 - Coveralls