fix: sort resource collections in YAML and register fetch command

[Ruari-Phipps]

Summary

Sorts collections alphabetically during YAML serialization so pulls produce stable, diff-friendly output. Also registers FetchCommand in the CLI command list — it was implemented but never wired up, so poly fetch was unavailable.

Motivation

Several collections are built by iterating a map in the platform projection — flow step conditions, API integration operations, test case function call assertions and their arguments, and the integration/operation keys of test case API mocks. Their serialized order followed whatever the map iteration gave, so unrelated pulls could reorder blocks in a resource's YAML and create noisy diffs.

Separately, the fetch command existed in cli_commands/sync.py but was missing from COMMANDS, so it never appeared in the CLI.

Changes

• FlowStep.to_yaml_dict sorts conditions by name (matches the existing sorted(self.extracted_entities) behaviour)
• ApiIntegration.to_yaml_dict sorts operations by name
• FunctionCallAssertion.to_yaml_dict sorts arguments by parameter_name, and TestCaseAssertion.to_yaml_dict sorts function call assertions by name
• TestCaseApiMocks.to_yaml_dict sorts integration and operation names; the rules within an operation keep their order, since they are a sequence and repeat depends on it
• Add FetchCommand to the COMMANDS list in cli.py so poly fetch is registered
• Add unit tests covering each ordering, including one asserting mock rule order is preserved
• uv.lock version bump picked up from the 0.44.4 release

Test strategy

• Added/updated unit tests
• Manual CLI testing (poly --help now lists fetch)
• Tested against a live Agent Studio project
• N/A (docs, config, or trivial change)

Checklist

• ruff check . and ruff format --check . pass
• pytest passes (1356 passed)
• No breaking changes to the poly CLI interface (or migration path documented)
• Commit messages follow conventional commits

Screenshots / Logs

$ uv run poly --help | grep fetch
    fetch               Fetch the latest project state from Agent Studio

[github-actions]

Coverage Report

Base (main)	PR	Change
75.9%	75.9%	+0.0% ✅

Changed file coverage

File	Coverage	Change
poly/cli_commands/sync.py	63.8%	+1.5% ✅

[oeisenberg]

See it, say it, sorted