A machine joins the mesh it raised

The last step of the first-node path, and the bundle now carries all of it: a
container runtime, the store, a database per context, their schemas, the broker
with a certificate it generated itself, and the control plane running.

Then the machine enrols against the mesh on its own disk. It dials the broker
over TLS, refuses anything but the pinned certificate, presents the one-time
secret with a public key it generated, and is told the name the mesh has for
it. Its specialness lasted two commands, which is what ADR 0004 asked for.

The identity is saved only after the mesh says it knows this node. A node
holding an identity the mesh never recorded would believe it had joined and be
believed by nobody, which is worse than not joining because nothing looks wrong.

An already-enrolled machine refuses a valid token rather than quietly acquiring
a second identity, and a spent token is refused by the mesh. Both checked.

Containers gained a network field. The control plane must reach the store and
the broker on the machine it was raised on, before there is any mesh to arrange
that; the alternative was publishing ports and guessing an address that works
from inside a container, which fails in a worse way.

The control plane talks to the broker over loopback in plaintext, deliberately.
The TLS on 5671 exists so a node crossing a network can pin a certificate, not
for a hop that never leaves the machine.

Verified on a sealed lab machine: eleven resources applied from bare, the
control plane consuming, a token issued from inside it, and the machine
enrolled -- with the recorded public key matching what the host printed, the
token marked spent, and the profile stored.

internal/declaration/declaration.go

@@ -168,6 +168,13 @@ type Container struct {
 	Ports   []string          `json:"ports,omitempty"`
 	Volumes []string          `json:"volumes,omitempty"`
 	Args    []string          `json:"args,omitempty"`
+	// Network is the container's network, passed to the runtime unchanged.
+	//
+	// Needed because the control plane must reach the store and the broker on the machine it was
+	// raised on, before there is any mesh to arrange that. The alternative was publishing ports
+	// and guessing an address that works from inside a container, which is the same thing with a
+	// worse failure mode.
+	Network string `json:"network,omitempty"`
 }
 
 func (c *Container) Identity() string { return c.ID }