Consider using model_dump for input/output config serialization

[yesudeep]

Summary

The Python Dotprompt implementation has TODOs about potentially using model_dump for cleaner serialization.

Locations

• python/dotpromptz/src/dotpromptz/dotprompt.py:420: # TODO: use meta.input.model_dump(exclude_none=True)?
• python/dotpromptz/src/dotpromptz/dotprompt.py:423: # TODO: use meta.output.model_dump(exclude_none=True)?

Acceptance Criteria

• Evaluate if model_dump provides cleaner serialization
• Ensure compatibility with all consumers
• Implement if beneficial