[build-tools] Load legacy command/path local functions and resolve module paths

[sswrk]

Why

How

Test Plan

[linear-code]

ENG-25402

[sswrk]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• [eas-cli] Validate legacy command/path local functions referenced from workflows #4098
• [build-tools] Load legacy command/path local functions and resolve module paths #4097 👈 (View in Graphite)
• [steps] Expand legacy command/path local functions to a single build step #4096
• [eas-build-job] Accept legacy command/path custom function shape in function.yml #4095
• [eas-cli] Validate local composite functions referenced from workflow hooks #4064
• [build-tools][steps] Load composite function catalogs for hook steps #4063
• [steps] Support local composite functions in hook steps #4062
• [steps] Unify the default gating of steps with no if: across steps, composite scopes, and hooks #4061
• [eas-cli] Validate local composite functions in workflow files #3931
• [build-tools] Load local composite function catalog at build runtime #3930
• [steps][4/4] Resolve composite function outputs #4015
• [steps][3/4] Interpolate composite function inputs #4014
• [steps][2/4] Expand composite function references into build steps #3929 : 1 other dependent PR (#4013 )
• [steps][1/4] Add isCompositeFunctionPath and reject local composite functions in custom builds #3956
• [eas-build-job] Add local composite function schema #3928
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[codecov]

Codecov Report

❌ Patch coverage is 94.11765% with 1 line in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (szymonswierk/eng-25402-steps-expand-legacy-functions@f0df7c2). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
...ckages/build-tools/src/steps/compositeFunctions.ts	66.67%	1 Missing ⚠️

Additional details and impacted files

@@                                   Coverage Diff                                   @@
##             szymonswierk/eng-25402-steps-expand-legacy-functions    #4097   +/-   ##
=======================================================================================
  Coverage                                                        ?   62.75%           
=======================================================================================
  Files                                                           ?     1000           
  Lines                                                           ?    45312           
  Branches                                                        ?     9513           
=======================================================================================
  Hits                                                            ?    28431           
  Misses                                                          ?    15434           
  Partials                                                        ?     1447           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[github-actions]

✅ Thank you for adding the changelog entry!