Update a match's lifecycle status

Transitions a match between lifecycle states (validated against allowed transitions). Requires the game.lifecycle:read-write permission. Supports an optional Idempotency-Key request header that deduplicates concurrent duplicate submissions: while one request is in flight, a second request with the same key and body resolves to the same outcome, and the same key with a different body returns 409 error_idempotency_key_conflict. The idempotency identity is scoped per match and per target status. Note that this endpoint validates the live match state first, so a sequential retry sent after the transition has already succeeded returns the normal transition error (error_match_not_in_valid_state) - the live state no longer permits the transition - rather than a replayed success.