Rename upgrade_subscription to change_repository_plan API

[jfrench9]

Summary

Refactors the subscription API by renaming upgrade_subscription.py to change_repository_plan.py, providing a more accurate and flexible API endpoint name that better reflects its purpose. The module has been significantly enhanced with improved logic and documentation.

Key Accomplishments

• API Rename: Renamed upgrade_subscription to change_repository_plan to better convey the endpoint's capability of handling repository-level plan changes (not just upgrades)
• Enhanced Implementation: Expanded the module with ~37 net new lines of logic, indicating improved handling of plan change scenarios (e.g., upgrades, downgrades, or lateral plan switches)
• Documentation Improvements: Updated docstrings and documentation in upgrade_subscription_request.py for improved clarity and consistency with the new naming convention
• Semantic Accuracy: The new naming aligns the API surface with the actual business operation — changing a repository's plan rather than generically "upgrading a subscription"

Breaking Changes

⚠️ Yes — this is a breaking change for consumers of the client library:

• robosystems_client.api.subscriptions.upgrade_subscription has been removed and replaced with robosystems_client.api.subscriptions.change_repository_plan
• Any code importing or referencing the old upgrade_subscription module will need to be updated to use change_repository_plan
• The UpgradeSubscriptionRequest model remains in place but its documentation has been updated

Testing Notes

• Verify that all existing subscription plan change workflows function correctly under the new API path
• Test both upgrade and downgrade scenarios to ensure the broadened semantics are properly supported
• Validate that the request model (UpgradeSubscriptionRequest) serializes and deserializes correctly with the renamed endpoint
• Ensure no stale references to the old upgrade_subscription module exist in dependent services or integration tests

Infrastructure Considerations

• Downstream services and CI pipelines that depend on the subscription API client should be updated to reference the new module name before or alongside this change
• Consider a coordinated rollout if multiple services consume this client library to avoid import errors
• Package version should be bumped appropriately (minor or major) to signal the breaking change to consumers

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🤖 Generated with Claude Code

Branch Info:

• Source: feature/repo-sub-change
• Target: main
• Type: feature

Co-Authored-By: Claude noreply@anthropic.com