create_initiative / update_initiative fails with "Object of type InitiativeState is not JSON serializable"

[uboesen]

Body:

Bug

Calling create_initiative or update_initiative with the state parameter fails with:

TypeError: Object of type InitiativeState is not JSON serializable

Steps to reproduce

Pass state="ACTIVE" (or any valid value) to create_initiative or update_initiative.

Suspicion

The issue may be related to how the InitiativeState enum is serialized when the Pydantic model is passed to the HTTP client. It looks like the enum instance is not being converted to
its string value before JSON serialization — but I have not traced the exact call stack.

Environment

• plane-mcp-server: 0.2.8