feat: add warning deduplicator

[TerryHowe]

What this PR does / why we need it:

Add a warning deduplicator and some tests for it. Gets a little bloat out of options/remote.go

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.21%. Comparing base (338759d) to head (bda2340).
⚠️ Report is 99 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1856      +/-   ##
==========================================
+ Coverage   87.18%   87.21%   +0.03%     
==========================================
  Files         143      144       +1     
  Lines        5539     5532       -7     
==========================================
- Hits         4829     4825       -4     
+ Misses        423      421       -2     
+ Partials      287      286       -1     

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[Copilot]

Pull Request Overview

This PR introduces a centralized warning handler to manage registry warnings and reduces code duplication. The change extracts warning handling logic from the Remote struct into a dedicated WarningHandler component with proper concurrency handling.

• Adds a new WarningHandler type with thread-safe warning deduplication
• Removes warning handling code from the Remote struct to reduce bloat
• Provides comprehensive test coverage for the new warning handler functionality

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
cmd/oras/internal/option/warning_handler.go	New warning handler implementation with sync.Map for thread-safe deduplication
cmd/oras/internal/option/warning_handler_test.go	Comprehensive test suite covering deduplication, concurrency, and multi-registry scenarios
cmd/oras/internal/option/remote.go	Removes old warning handling code and integrates new WarningHandler
cmd/oras/internal/option/binary_target.go	Removes manual warning map initialization that's no longer needed

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[Copilot]

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

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[Wwwsylvia]

I found the name warningHandler and warned a bit hard to understand... I don't have a good suggestion though. Is it more like a warner pool or something?

[TerryHowe]

Sounds good. I renamed to warningDeduplicator and the warner is now seen

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

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[TerryHowe]

This is ready for review

[github-actions]

This PR is stale because it has been open 45 days with no activity. Remove stale label or comment or this will be closed in 30 days.

[TerryHowe]

I'd like to hold this open, but right now the plan is to include the warning deduplicator in oras-go. I took the feedback from this PR and included it in the oras-go code. If for some reason that doesn't work out, we can revert to this PR.

[TerryHowe]

This will be handled by oras-go v3