Undefine CONTROL and the controller's consumers, its followed events and its lease reading

The controller ended (ADR 0590): nothing consumes what nodes report on CONTROL, so the mesh no
longer declares the stream, which would make it again before its removal; MeshConsumers is empty,
the controller's consumers and the events it followed go, and the lease holder's reading
(LeaseHolder, LeaseHandedAway) with them. Only the consumers' names stay, for the removal of the
leftovers and the watchman's read of whether controller still stands. Issue 1126 B3b.

Claude-Session: https://claude.ai/code/session_01NcbgfJ9Gum47zkFKWRaovL

go/buscompose/raise.go

@@ -16,7 +16,7 @@ type Raiser interface {
 	Ensurer
 }
 
-// Raise asserts the mesh's streams, the controller's own consumers, and one consumer per node.
+// Raise asserts the mesh's streams, its own consumers, and one consumer per node.
 //
 // **The order is not a preference.** A consumer on a stream that does not exist is refused, and the
 // refusal names the stream rather than the order — so somebody reading it goes looking for a deleted