mesh-vault: retire and rotate without the controller's lease

The controller ended by its unassignment and its lease key expired, so the
gate on a handed lease kept retirement, rotation and node-login rotation off
for good (issue 1126, A3). Drop the gate, the lease watch and the manifest's
read of mesh-controller.lease; vault_status no longer reports a lease.

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

modules/mesh-vault/module.json

@@ -32,7 +32,6 @@
   "reads": [
     "node-engine.have",
     "mesh-grants.accounts",
-    "mesh-controller.lease",
     "mesh-delivery-assigner.placement",
     "mesh-provisioner.plans",
     "mesh-provisioner.provisions"