Fix #77: rename_arguments double-partial bug

[hmgaudecker]

Summary

• Fix rename_arguments wrapping partial inputs in a second functools.partial, which caused bound arguments to be passed twice
• Use get_free_arguments to filter the wrapper's signature to only truly free parameters, instead of re-implementing partial keyword detection
• Add 6 tests covering rename_arguments with functools.partial inputs

Details

The old code had a "Preserve function type" block that wrapped the closure in functools.partial(wrapper, *func.args, **func.keywords). This re-bound arguments that were already captured by the closure's call to func(...), causing double-passing.

The fix removes that block and instead filters keyword-bound parameters out of the wrapper's signature using the existing get_free_arguments helper, keeping a single source of truth for which parameters are free.

Test plan

• All 175 dags tests pass
• Downstream: gettsim — 2470 passed (1 unrelated failure: missing SOEP data file)
• Downstream: pylcm — 726 passed
• Downstream: skillmodels — 351 passed

Closes #77

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.70%. Comparing base (ca4c296) to head (68b07b3).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #78      +/-   ##
==========================================
+ Coverage   96.61%   96.70%   +0.08%     
==========================================
  Files          26       26              
  Lines        1272     1306      +34     
==========================================
+ Hits         1229     1263      +34     
  Misses         43       43              

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[hmgaudecker]

Autoreview.

[hmgaudecker]

Messed up in multiple ways; fixed in #79