Interrupt and other control calls stall when nobody is reading messages

Control Protocol Query routes control responses and conversation messages through one reader task. That task awaits a send into a 100-message buffer (query.py:229, 506), so when the caller is not iterating receive_messages and the buffer fills, the control_response for interrupt(), set_model() or get_mcp_status() is never routed and the call fails after 60 seconds with Control request timeout. Only an example script warns that interrupts require active consumption.

Impact: The escape hatch fails exactly when it is needed: a runaway turn with partial messages enabled fills the buffer in seconds, and interrupt() then times out instead of stopping it.

Recommendation (small effort): Route control_response frames before any await on the message buffer, or give control responses their own path that never waits on the consumer. Document the consumption requirement on interrupt() itself.