Add allowed_keyword arguments to fm_steps

[larsevj]

Issue
Resolves #12281

• 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 screenshots are changed: Review screenshot-PR in ert-testdata,
  merge screenshot-PR in ert-testdata before merging this PR.
• 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

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.93%. Comparing base (40ae884) to head (d683bb7).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14104      +/-   ##
==========================================
- Coverage   91.94%   91.93%   -0.02%     
==========================================
  Files         482      482              
  Lines       33493    33507      +14     
==========================================
+ Hits        30794    30803       +9     
- Misses       2699     2704       +5     

Flag	Coverage Δ
cli-tests	36.25% <66.66%> (+0.02%)	⬆️
fuzz	44.24% <52.38%> (+<0.01%)	⬆️
gui-tests	58.61% <52.38%> (-0.01%)	⬇️
performance-and-unit-tests	80.80% <100.00%> (-0.01%)	⬇️
test	46.05% <19.04%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/ert/config/ert_config.py	95.89% <100.00%> (-0.12%)	⬇️
src/ert/config/forward_model_step.py	98.77% <100.00%> (+0.10%)	⬆️
...lugins/hook_implementations/forward_model_steps.py	94.66% <ø> (-0.11%)	⬇️

... and 1 file with indirect coverage changes

[berland]

Unset means None. Better to be precise about that, and maybe explicitly state that an empty list is not the same as "unset".

[Copilot]

Pull request overview

Adds opt-in validation for plugin forward-model keyword arguments.

Changes:

• Introduces allowed_keywords and aggregated keyword validation.
• Applies strict validation to reservoir simulator steps.
• Adds tests, documentation, and updated serialization snapshots.

Reviewed changes

Copilot reviewed 26 out of 26 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/ert/config/forward_model_step.py	Defines and validates allowed keywords.
src/ert/config/ert_config.py	Runs allowed and required keyword checks.
src/ert/plugins/hook_implementations/forward_model_steps.py	Restricts reservoir simulator keywords.
tests/ert/unit_tests/config/test_forward_model.py	Tests keyword contracts and simulator validation.
docs/ert/getting_started/howto/plugin_system.rst	Documents the plugin API.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_single_test_run_matches_snapshot/snake_oilsnake_oil.ert/snake_oil.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_single_test_run_matches_snapshot/poly_examplepoly.ert/poly.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_single_test_run_matches_snapshot/heat_equationconfig.ert/config.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_manual_update_matches_snapshot/snake_oilsnake_oil.ert/snake_oil.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_manual_update_matches_snapshot/poly_examplepoly.ert/poly.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_manual_update_matches_snapshot/heat_equationconfig.ert/config.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_evaluate_ensemble_matches_snapshot/snake_oilsnake_oil.ert/snake_oil.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_evaluate_ensemble_matches_snapshot/poly_examplepoly.ert/poly.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_evaluate_ensemble_matches_snapshot/heat_equationconfig.ert/config.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_esmda_matches_snapshot/snake_oilsnake_oil.ert/snake_oil.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_esmda_matches_snapshot/poly_examplepoly.ert/poly.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_esmda_matches_snapshot/heat_equationconfig.ert/config.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_ensemble_smoother_matches_snapshot/snake_oilsnake_oil.ert/snake_oil.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_ensemble_smoother_matches_snapshot/poly_examplepoly.ert/poly.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_ensemble_smoother_matches_snapshot/heat_equationconfig.ert/config.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_ensemble_experiment_matches_snapshot/snake_oilsnake_oil.ert/snake_oil.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_ensemble_experiment_matches_snapshot/poly_examplepoly.ert/poly.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_ensemble_experiment_matches_snapshot/heat_equationconfig.ert/config.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_enif_matches_snapshot/snake_oilsnake_oil.ert/snake_oil.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_enif_matches_snapshot/poly_examplepoly.ert/poly.json	Updates serialized schema snapshot.
tests/ert/unit_tests/run_models/snapshots/test_experiment_serialization/test_that_dumped_enif_matches_snapshot/heat_equationconfig.ert/config.json	Updates serialized schema snapshot.

[larsevj]

For flow and eclipse this would change a warning to a ConfigValidationError now.

[codspeed-hq]

Merging this PR will not alter performance

✅ 36 untouched benchmarks

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_{Comparing larsevj:add_allowed_keywords_fm_steps (d683bb7) with main (40ae884)}