fix: rest namespace integration with table version apis

[jackye1995]

During testing, found some issue with RestNamespace implementation of the table versions API, which was not 100% according to the spec definition.

[github-actions]

PR Review

Summary

This PR aligns the RestNamespace implementation with the Lance namespace spec, changing HTTP methods and paths for list_table_versions and describe_table_version APIs.

Potential Issue (P1)

list_table_versions body serialization (rest.rs:1189):

self.post_json(&path, &query, &(), "list_table_versions", &id)

Passing &() as the body will serialize to JSON null. If the server expects an empty object {} or validates that the body is not null, this could cause runtime failures. Consider:

• Confirming the spec allows null body for this POST endpoint, OR
• Using an empty struct or serde_json::Value::Object that serializes to {} if needed

Minor Observations

1. No test coverage for changed endpoints: The list_table_versions and describe_table_version methods don't have dedicated tests with wiremock. Consider adding tests that validate the HTTP method (POST), path (/version/list, /version/describe), and body format to prevent future regressions.

2. Python create_table_version_json additions: The new JSON wrapper methods look correct for Rust FFI compatibility. The pattern matches similar methods in the codebase.