[WIP] Add node-local delayed resume to ProcessorInbox

[lquerel]

Not ready for review. #2470 must be merged first to reduce the scope of this PR

Change Summary

Add node-local delayed pdata resume for processors via requeue_later(...) and integrate it into ProcessorInbox.

This PR extends the node-local scheduler work from the previous PR by adding a bounded local delayed-resume reservoir for pdata. Due delayed resumes are delivered back through ProcessorInbox, and retry_processor is migrated off the old global delayed-data path.

This is the next step in the redesign tracked in #2465. After PR3 separated wakeup-style local scheduling from delayed pdata handling, this PR addresses the delayed pdata side directly.

The goal is to move retry-style deferred work out of the global runtime path and into node-local inbox orchestration, while keeping the old global delayed-data plumbing in place temporarily for compatibility. That keeps this PR focused on local delayed resume and retry migration only; the cleanup and removal of the old global path happens in the next PR.

What issue does this PR close?

• Part of Improve control delivery, shutdown robustness, and local deferred work #2465

How are these changes tested?

• Added/updated engine tests covering:
  • local delayed resume scheduling
  • bounded delayed-resume delivery through ProcessorInbox
  • shutdown behavior for pending delayed resumes
• Added/updated retry processor tests covering:
  • retry rescheduling through requeue_later(...)
  • retry behavior after delayed local resume
• cargo xtask check

Are there any user-facing changes?

No user-facing changes.

This PR is an internal runtime change only.

[codecov]

Codecov Report

❌ Patch coverage is 77.94261% with 907 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.21%. Comparing base (5ef4ab5) to head (374af82).
⚠️ Report is 11 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2471      +/-   ##
==========================================
- Coverage   88.35%   88.21%   -0.14%     
==========================================
  Files         603      608       +5     
  Lines      212379   216476    +4097     
==========================================
+ Hits       187646   190971    +3325     
- Misses      24207    24979     +772     
  Partials      526      526              

Components	Coverage Δ
otap-dataflow	90.14% <77.94%> (-0.24%)	⬇️
query_abstraction	80.61% <ø> (ø)
query_engine	90.74% <ø> (ø)
syslog_cef_receivers	∅ <ø> (∅)
otel-arrow-go	52.44% <ø> (ø)
quiver	91.94% <98.90%> (+0.03%)	⬆️

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