[CLN]: add CreateSegment type

[codetheweb]

Description of changes

Adds back the CreateSegment type that was removed in #4550

Test plan

How are these changes tested?

• Tests pass locally with pytest for python, yarn test for js, cargo test for rust

Documentation Changes

Are all docstrings for user-facing APIs updated if required? Do we need to make documentation changes in the docs section?

n/a

[propel-code-bot]

Reintroduce CreateSegment Type for Segment Creation Operations

This PR adds back the CreateSegment type that was previously removed in PR #4550. The change replaces all usages of the Segment type in segment creation contexts with the more specifically-purposed CreateSegment type, allowing for clearer distinction between creation operations and existing segment representations.

Key Changes:
• Added CreateSegment struct to model/segment.go
• Added CreateSegmentToSegment helper function to convert between types
• Updated all segment creation code paths to use CreateSegment instead of Segment

Affected Areas:
• go/pkg/sysdb/coordinator/model
• go/pkg/sysdb/coordinator
• go/pkg/sysdb/grpc

This summary was automatically generated by @propel-code-bot

[github-actions]

Reviewer Checklist

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Testing, Bugs, Errors, Logs, Documentation

• Can you think of any use case in which the code does not behave as intended? Have they been tested?
• Can you think of any inputs or external events that could break the code? Is user input validated and safe? Have they been tested?
• If appropriate, are there adequate property based tests?
• If appropriate, are there adequate unit tests?
• Should any logging, debugging, tracing information be added or removed?
• Are error messages user-friendly?
• Have all documentation changes needed been made?
• Have all non-obvious changes been commented?

System Compatibility

• Are there any potential impacts on other parts of the system or backward compatibility?
• Does this change intersect with any items on our roadmap, and if so, is there a plan for fitting them together?

Quality

• Is this code of a unexpectedly high quality (Readability, Modularity, Intuitiveness)