Two-node DB-consumer bed + a scenario disk field

The GREEN multi-node regression bed that proves the DB-consumer gate: substrate/control on
one node, postgres+redis providers and baserow+letta consumers on another, each consumer
getting its own credential and its own mesh-named database across the overlay. Requires the
mesh-control provider-seal-key fix and the mesh-catalog db-name fix.

Includes a general lab capability: a machine 'disk' field sizing the VM root disk (a broad
install exhausts the pool default and the host fails mid-apply with 'no space left on
device'). The bed sets 60GiB.

Claude-Session: https://claude.ai/code/session_01LrgweAeERJYBg88c5cKDzF

src/declaration/parse.ts

@@ -40,6 +40,7 @@ function normaliseMachine(raw: unknown): Machine {
   if (machine["egress"] === true) result.egress = true;
   if (machine["memory"] !== undefined) result.memory = String(machine["memory"]);
   if (machine["cpus"] !== undefined) result.cpus = Number(machine["cpus"]);
+  if (machine["disk"] !== undefined) result.disk = String(machine["disk"]);
   return result;
 }