[WIP] feat(metrics): refactor retry processor telemetry

[lquerel]

Change Summary

What issue does this PR close?

• Closes #NNN

How are these changes tested?

Are there any user-facing changes?

Changelog

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

[opentelemetry-pr-dashboard]

Pull request dashboard status

Status last refreshed: 2026-07-22 19:58:06 UTC.

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[codecov]

Codecov Report

❌ Patch coverage is 92.05298% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.71%. Comparing base (63cc7e5) to head (93407f8).

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #3544    +/-   ##
========================================
  Coverage   86.71%   86.71%            
========================================
  Files         792      792            
  Lines      320291   320401   +110     
========================================
+ Hits       277736   277839   +103     
- Misses      42031    42038     +7     
  Partials      524      524            

Components	Coverage Δ
otap-dataflow	87.74% <92.05%> (+<0.01%)	⬆️
query_engine	89.57% <ø> (ø)
otel-arrow-go	52.45% <ø> (ø)
quiver	92.20% <ø> (ø)

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