Switch to UV

[MonkeyCanCode]

Summary

As per ML, we want to proceed with more standard layout for python project by using uv. Here are the changes made in this PR:

1. Applied PEP 639 to python based model and converters
2. Converted snowflake and honeydew converter to modern pyproject layout and modularized
3. Remove un-necessary settings in pyprojects such as pythonpath = ["src"]
4. Sorted the sections in pyprojects alphabetically
5. Chcked-in uv.lock per project

Related Issues

Checklist

Specification

• Spec changes are included in core-spec/ and follow the existing structure
• Spec changes have been discussed on the mailing list or in a linked issue
• Breaking changes to the spec are clearly called out in the summary

Ontology

• Ontology changes in ontology/ are consistent with spec changes
• New or modified terms are defined and documented

Converters

• Converter logic in converters/ is updated to reflect spec or ontology changes
• New converters include tests under the converter's test directory

Validation

• Validation rules in validation/ are updated if the spec changed
• New validation cases are covered by tests

Documentation

• docs/ is updated to reflect any user-facing changes
• New features or behaviors are documented with examples where appropriate
• CONTRIBUTING.md is updated if the contribution process changed

Examples

• examples/ are added or updated for any new spec constructs or converter support

Tests

• All existing tests pass (pytest / CI green)
• New functionality is covered by tests

Compliance

• ASF license headers are present on all new source files
• No third-party dependencies are added without PMC/IPMC approval