[steps] Support local composite functions in hook steps

[sswrk]

Why

Hook steps currently reject uses: ./... local composite functions. Users should be able to reuse the same composites in hooks as in the main workflow.

How

A composite function used in a hook is expanded into its inner steps at parse time, the same way it is in the main workflow, and the whole expansion becomes a single hook entry. The step's if: gates the expansion as a whole.

Hook construction now takes a catalog of composite functions. Without it, referencing a composite fails with a missing-function error instead of the previous "not supported in hooks" error.

Wiring reading the composite functions files will be added in follow-up PRs in the stack.

Test Plan

Added unit tests.

[linear-code]

ENG-22387

[sswrk]

• [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
• [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][build-tools][steps] Validate local composite functions referenced from workflow hooks; extract the shared loader into steps #4064
• [build-tools][steps] Load composite function catalogs for hook steps #4063
• [steps] Support local composite functions in hook steps #4062 👈 (View in Graphite)
• [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

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 62.32%. Comparing base (ee03114) to head (e260a74).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4062      +/-   ##
==========================================
+ Coverage   62.32%   62.32%   +0.01%     
==========================================
  Files         995      995              
  Lines       44923    44933      +10     
  Branches     9440     9443       +3     
==========================================
+ Hits        27992    28002      +10     
  Misses      15483    15483              
  Partials     1448     1448              

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[sswrk]

@hSATAC Thank you for noting that, and yes, this was done like that for the sake of consistency. But taking a step back, as a user I'd expect composite functions/function groups to fast-fail within them even in the after_* hook (and then let the next steps in the hook run).

Corrected the behavior for both composite functions and function groups.

[github-actions]

⏩ The changelog entry check has been skipped since the "no changelog" label is present.