feat(telemetry): add runtime EventName filtering for internal logs

[cijothomas]

Change Summary

Adds EventName-level filtering for df_engine internal telemetry logs. The new engine.telemetry.logs.events configuration is combined with the existing level and target filter, and supports mutually exclusive allow and deny lists with exact or trailing-wildcard prefix patterns.

engine:
  telemetry:
    logs:
      level: "info"
      events:
        allow:
          - "receiver.start"
          - "channel.*"

The filter reads the OpenTelemetry EventName from tracing::Metadata::name(). Because the EventName is static for each tracing callsite, the filter caches an Interest::always() or Interest::never() decision instead of evaluating the policy for every event. Policy updates use ArcSwap for atomic replacement and rebuild tracing's callsite interest cache, moving matching cost to configuration updates and keeping it off the emission hot path.

Successful full-engine reconciliation applies the validated EventName policy to the shared runtime filter, including configuration received through the OpAMP controller extension. Failed or invalid reconciliation preserves the active filter.

What issue does this PR close?

Relates to #3387

Are there any user-facing changes?

Yes. Users can filter internal telemetry logs by EventName through static configuration or full-engine remote configuration without restarting the engine or rebuilding tracing subscribers.

Changelog

• Added a .chloggen/*.yaml entry
• This PR is a chore (indicated in title)
• This is a documentation-only PR.

[codecov]

Codecov Report

❌ Patch coverage is 98.71383% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.52%. Comparing base (4ab1d24) to head (a14ccbc).

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #3511    +/-   ##
========================================
  Coverage   86.51%   86.52%            
========================================
  Files         782      783     +1     
  Lines      313105   313396   +291     
========================================
+ Hits       270893   271169   +276     
- Misses      41688    41703    +15     
  Partials      524      524            

Components	Coverage Δ
otap-dataflow	87.55% <98.71%> (+<0.01%)	⬆️
query_engine	89.57% <ø> (ø)
otel-arrow-go	52.45% <ø> (ø)
quiver	92.19% <ø> (ø)

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[opentelemetry-pr-dashboard]

Pull request dashboard status

Status last refreshed: 2026-07-22 19:57:38 UTC.

• Waiting on: Author
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