fix: Don't show diff for reordered entities

[Ruari-Phipps]

Summary

Fix spurious diffs after push caused by extracted_entities list ordering differences between local YAML and the platform.

Motivation

After pushing, poly diff shows reordering-only changes to extracted_entities in flow steps. The platform returns entity IDs in a different order than local YAML, producing false diffs with no meaningful content change.

Changes

• Sort extracted_entities in FlowStep.to_yaml_dict() so both local and remote representations use a consistent alphabetical order

Test strategy

• Added/updated unit tests
• Manual CLI testing (poly <command>)
• Tested against a live Agent Studio project
• N/A (docs, config, or trivial change)

Checklist

• ruff check . and ruff format --check . pass
• pytest passes
• No breaking changes to the poly CLI interface (or migration path documented)
• Commit messages follow conventional commits

Screenshots / Logs

[github-actions]

Coverage Report

Base (main)	PR	Change
71.8%	71.8%	+0.0% ✅