[build-tools] Upload workflow job outputs

[sjchmiela]

Summary

This uploads declared workflow job outputs from @expo/build-tools for both step-based and normal build execution paths.

This PR is stacked on top of #3704, which preserves outputs in Android/iOS build job payloads.

Changes

• Add a build-context output upload path for normal Android/iOS builds.
• Reuse the existing step-context output upload path for custom/repack builds so steps.*.outputs.* references still work.
• Upload outputs during normal build finalization, including failure/finalization-failure paths, with success() and failure() reflecting the final result.
• Skip output upload cleanly when outputs are absent or cloud workflow upload context is unavailable.
• Add tests for custom build upload, normal build success/failure/finalization failure upload, build-context interpolation, and skip behavior.

Validation

• packages/build-tools: yarn test builders/__tests__/custom.test.ts builders/__tests__/common.test.ts utils/__tests__/outputs.test.ts
• packages/build-tools: yarn build
• yarn oxfmt --check ...

[github-actions]

Subscribed to pull request

File Patterns	Mentions
**/*	@douglowder

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[codecov]

Codecov Report

❌ Patch coverage is 59.09091% with 27 lines in your changes missing coverage. Please review.
✅ Project coverage is 56.64%. Comparing base (f856d40) to head (09c7fd9).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/build-tools/src/utils/outputs.ts	50.00%	24 Missing ⚠️
packages/build-tools/src/builders/common.ts	85.72%	2 Missing ⚠️
packages/build-tools/src/builders/custom.ts	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3705      +/-   ##
==========================================
+ Coverage   56.59%   56.64%   +0.05%     
==========================================
  Files         888      889       +1     
  Lines       38496    38578      +82     
  Branches     8026     8036      +10     
==========================================
+ Hits        21784    21849      +65     
- Misses      16614    16632      +18     
+ Partials       98       97       -1     

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[github-actions]

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