Post v0 city by city name session by ID reset

Requests a fresh restart of an existing session: the session bead is kept, and the controller restarts the runtime on the next continuation epoch, so the provider starts a new conversation instead of resuming the previous one. The call records the request and pokes the controller; it returns before the restart happens. A closed session returns 409. For a named session, the controller clears a tripped respawn circuit breaker when its next tick consumes the restart request through the restart path. Unlike gc session reset, this endpoint does not clear the breaker synchronously, so the clear does not happen if the controller never processes the request, and it also does not happen when a session drain-acks in the same window: the drain-ack path consumes the restart request without touching the breaker. Use gc session reset when clearing the breaker is itself the goal. This endpoint always requests an in-place restart. Unlike gc session reset, it never rolls back an unfinished create, so a session wedged mid-create is retried in place instead of being replaced; use gc session reset to roll one back.