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/lifecycle/raise.ts

@@ -167,6 +167,7 @@ async function createMachine(
   egress = false,
   memory = "1GiB",
   cpus = 2,
+  disk?: string,
 ): Promise<string> {
   const name = machineName(instanceId, machine);
   if (await succeeds(["config", "show", name], 15_000)) return name;
@@ -183,6 +184,9 @@ async function createMachine(
     "-c", `user.mesh-lab.instance=${instanceId}`,
     "-c", `user.mesh-lab.machine=${machine}`,
   ];
+  // A bigger root disk than the pool default, when the scenario asks — a broad install stocks many
+  // images and exhausts the default, failing the apply with "no space left on device".
+  if (disk) args.push("-d", `root,size=${disk}`);
   await incus(args, 300_000);
 
   // eth0 comes from the profile and points at the wrong network, so every attachment is
@@ -285,7 +289,7 @@ export async function raise(
       const attachments = spec.at === "detached" ? [] : spec.at;
       const name = await createMachine(
         instanceId, machine, attachments, image, pool,
-        spec.at !== "detached" && spec.egress === true, spec.memory, spec.cpus);
+        spec.at !== "detached" && spec.egress === true, spec.memory, spec.cpus, spec.disk);
       created.push(name);
       byMachine.set(machine, name);
       log(`  machine ${machine}${spec.at === "detached" ? " (detached)" : ""}`);