Fix wrong source package in forward models doc

[HakonSohoel]

Some forward models wrongly stated ert as the source package due to ert being the default source_package value in the
ForwardModelStepDocumentation class.
With this commit the source package of the ForwardModelStepPlugin will be used as default value if it is not set explicitly.

Issue
Resolves #12402

Approach

• Added test to check if the source package returned by forward_model_steps matches their actual source package
• Installed some packages containing installable_forward_model_steps and verified that the test failed
• Introduced a get_source_package function that will make the forward module documentation use the correct package by default
• Verified that the test passed

Checklist

• PR title captures the intent of the changes, and is fitting for release notes.
• Added appropriate release note label
• Commit history is consistent and clean, in line with the contribution guidelines.
• Make sure unit tests pass locally after every commit (git rebase -i main --exec 'just rapid-tests')

When applicable

• When there are user facing changes: Updated documentation
• New behavior or changes to existing untested code: Ensured that unit tests are added (See Ground Rules).
• Large PR: Prepare changes in small commits for more convenient review
• Bug fix: Add regression test for the bug
• Bug fix: Add backport label to latest release (format: 'backport release-branch-name')

[codecov-commenter]

Codecov Report

❌ Patch coverage is 90.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 90.64%. Comparing base (e0162ab) to head (2255126).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
src/ert/config/forward_model_step.py	90.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #12670      +/-   ##
==========================================
- Coverage   90.68%   90.64%   -0.04%     
==========================================
  Files         429      429              
  Lines       29804    29817      +13     
==========================================
  Hits        27028    27028              
- Misses       2776     2789      +13     

Flag	Coverage Δ
cli-tests	37.56% <30.00%> (-0.01%)	⬇️
gui-tests	69.32% <30.00%> (-0.08%)	⬇️
performance-and-unit-tests	73.92% <90.00%> (-0.02%)	⬇️
test	38.06% <30.00%> (-0.01%)	⬇️

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[Copilot]

Pull request overview

This PR fixes a bug where forward model steps were incorrectly reporting "ert" as their source package in the documentation. The issue was caused by using a hardcoded default value in the ForwardModelStepDocumentation class. The fix uses stack inspection to automatically determine the correct source package from the calling plugin module.

Changes:

• Added a new test to verify that forward model step documentation correctly reports the source package of its parent plugin
• Introduced get_source_package() function that uses stack inspection to dynamically determine the source package
• Changed ForwardModelStepDocumentation.source_package field to use default_factory=get_source_package instead of a hardcoded "ert" default

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
tests/ert/unit_tests/docs/test_ert_documentation.py	Adds regression test that verifies forward model documentation reports correct source package
src/ert/config/forward_model_step.py	Implements stack inspection to automatically determine source package for documentation

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing HakonSohoel:fix-wrong-source-package-in-docs (2255126) with main (f0d9de4)}

Summary

✅ 22 untouched benchmarks