fix pre_hooks

[braingram]

Closes #203

Fixes pre-hooks by packing pre-hook results as tuples so they can be unpacked for subsequent hooks and step.

JWST regtests: https://github.com/spacetelescope/RegressionTests/actions/runs/12659199288
Romancal regtests: https://github.com/spacetelescope/RegressionTests/actions/runs/12659196940

Tasks

• update or add relevant tests
• update relevant docstrings and / or docs/ page
• Does this PR change any API used downstream? (if not, label with no-changelog-entry-needed)
  • write news fragment(s) in changes/: echo "changed something" > changes/<PR#>.<changetype>.rst (see below for change types)
  • run regression tests with this branch installed ("git+https://github.com/<fork>/stpipe@<branch>")
    • jwst regression test
    • romancal regression test

news fragment change types...

• changes/<PR#>.feature.rst: new feature
• changes/<PR#>.bugfix.rst: fixes an issue
• changes/<PR#>.doc.rst: documentation change
• changes/<PR#>.removal.rst: deprecation or removal of public API
• changes/<PR#>.misc.rst: infrastructure or miscellaneous change

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.27%. Comparing base (a2a8d46) to head (1acb486).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #214      +/-   ##
==========================================
+ Coverage   95.22%   95.27%   +0.04%     
==========================================
  Files          37       37              
  Lines        3165     3177      +12     
==========================================
+ Hits         3014     3027      +13     
+ Misses        151      150       -1     

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[tapastro]

Looks good!

[jdavies-st]

🎉 Thanks!