Fix Python codegen synthetic permission approval names

[abhinavgautam01]

Summary

Fixes Python codegen emitting an unintended quicktype-synthesized permission approval class name, PermissionDecisionApproveForIonApproval, caused by structural merging of similar permission approval schemas.

The generator now removes unreferenced synthetic dataclasses after union post-processing, preserving the intended schema-named union aliases such as PermissionDecisionApproveForSessionApproval and PermissionDecisionApproveForLocationApproval.

Fixes #1125.

Changes

• Added Python codegen cleanup for unused synthetic dataclasses
• Regenerated python/copilot/generated/rpc.py
• Added regression coverage to ensure the bad synthesized name is not exported while the intended long names remain available

Tests

• npm run generate:python
• python3 -m pytest python/test_codegen_type_names.py
• PATH=/Users/gautam/.nvm/versions/node/v22.14.0/bin:$PATH python3 -m pytest python/test_*.py
• git diff --check

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR updates the Python codegen post-processing to remove unused “synthetic” Quicktype-emitted @dataclass classes so they no longer appear in the generated module exports.

Changes:

• Added a post-processing pass to delete unreferenced synthetic @dataclass blocks from generated Python.
• Wired the new pass into the Python codegen pipeline using the schema’s known definition names.
• Added a Python regression test and updated the generated rpc.py output accordingly.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 3 comments.

File	Description
scripts/codegen/python.ts	Adds removeUnusedSyntheticPythonDataclasses() and applies it during final Python code post-processing.
python/test_codegen_type_names.py	Adds a regression test asserting a known synthetic type is not exported while real types remain exported.
python/copilot/generated/rpc.py	Regenerated output removing the unused synthetic dataclass and its __all__ export entry.