The lab had a registry that production does not, so it tested a fiction

The lab raised a `registry` VM, pushed ~73 images into it from the workstation, and
rewrote every manifest reference — third-party ones included — to point at it. No
production mesh has such a thing. So every bed proved that a machine could fetch an
image from a registry that exists nowhere else, and the bootstrap problems that only
appear when a machine has to fetch for itself went unfound.

What replaces it is the two things that are true in the world:

**Public images come from the public internet.** mesh-lab already created a NAT'd
uplink for exactly this and attached it to any machine declaring `egress`; no scenario
ever declared it. They do now, and third-party references are left exactly as the
catalogue writes them.

**The mesh's own images have no registry and never will.** mesh-control, mesh-builder,
mesh-route-proxy and the per-module runtimes are built from source and exist in no
registry. A machine gets them the way an operator's machine does — they are built here
and loaded onto it — and is then named by the digest of its own image configuration,
which mesh-host now accepts as "an image this machine already holds".

`images:` therefore means only *ours*, and a third-party entry is refused rather than
quietly loaded: otherwise the fiction returns one convenient line at a time. It is
per-machine as well, because "everything, everywhere" was never a description of
anything real — handing whole-mesh-full's union to its two 30GiB workstations would
fill the disk with runtimes nothing on them will start.

**The uplink and the declared gateway would have fought, silently.** A gateway container
and the transit router reach the scenario and nothing else; a default route through
either is a black hole for anything outside, and it beats the uplink's DHCP route on
metric. So a machine with egress states the scenario's ranges explicitly — through the
same gateway or transit it would have defaulted to, so the overlay-across-NAT path is
unchanged — and leaves the default to the uplink. A range with no path inside the
scenario becomes `unreachable` rather than falling through: 192.168.1.0/24 is an
ordinary private range in fact, and letting it escape would put scenario traffic on
whatever network the workstation is sitting on. `scenarioRoutesFor` is pure and tested,
because a decision only a full raise could check is one nobody checks.

The registry-reachability check the raise gained earlier is kept, pointed at the real
thing: every machine with egress must resolve a name and reach the internet before the
raise says it finished. Same failure it was written for — a raise that returns, an apply
that dies on its first pull, an instance left a bare shell — now guarding the path that
actually carries.

The base image's trust of the documentation ranges as plain-HTTP registries STAYS. It
was never only for the lab's registry: the mesh has one of its own, the `registry`
module, serving artifacts to the whole mesh over plain HTTP from whatever node runs it.

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

src/declaration/parse.ts

@@ -41,6 +41,9 @@ function normaliseMachine(raw: unknown): Machine {
   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"]);
+  // Absent and empty are different: absent means "all of the scenario's images", an explicit empty
+  // list means "none". A machine that runs nothing of ours should be able to say so.
+  if (machine["images"] !== undefined) result.images = toList(machine["images"]);
   return result;
 }