JP-3944: New ref file type for NIRSpec chromaticity correction

[emolter]

Relates to JP-3944

See companion JWST PR here: spacetelescope/jwst#10556

This PR adds a new reference file type in support of the NIRSpec IFU chromaticity correction.

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 jwst regression tests with this branch installed ("git+https://github.com/<fork>/stdatamodels@<branch>")

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 90.72%. Comparing base (a1358d6) to head (ca4bdaf).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #743      +/-   ##
==========================================
+ Coverage   90.71%   90.72%   +0.01%     
==========================================
  Files          99       99              
  Lines        4597     4605       +8     
==========================================
+ Hits         4170     4178       +8     
  Misses        427      427              

☔ 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.

[emolter]

regtests against jwst main: https://github.com/spacetelescope/RegressionTests/actions/runs/26053354958

regtests against jwst PR branch: https://github.com/spacetelescope/RegressionTests/actions/runs/26053406592

[melanieclarke]

LGTM, but would be helpful to have another datamodels expert review.

@braingram - this is still in draft because it needs CRDS support before we can move forward, but an advance review would be helpful if you have time.

[braingram]

Thanks. Changes look complete to me.

I pulled down one of the example files from the JP ticket and it has a defined lamp_mode of N/A but the rmap for https://jira.stsci.edu/browse/CRDS-1113 doesn't list that as part of the selector so likely if it is an "issue" that lamp_mode exists it's one with the reference file and not with the datamodel. My initial reaction is that's it's inconsequential but I figured I'd mention it here in case I'm mistaken.

[melanieclarke]

Let's go ahead and merge this since it will have no impact with jwst on main, and is working with the files available on CRDS test. One less thing to remember to do later when CRDS test merges with ops...