v2 partition schema: capability model, fixed sizing, and a proven rolling migration

The fleet's disk layout was decided by literal role-name comparisons at 17
sites across 8 files. That is why `labcontroller` got no rancher LV (it
matched neither "infra" nor "worker"), why labmaster carried an empty 728 GiB
Longhorn LV, and why a 62 GiB container image tipped that node into
DiskPressure and evicted bastion, labd, cockroach and openbao.

Three generators each hardcoded their own sizes and disagreed: the kickstart
said rancher=120G, ubuntu-autoinstall said 20G, asahi-firstboot said 20G under
a comment asserting the sizes matched install.ks.ts. They did not.

ROLE_REGISTRY already carried `k3s` and `parent` and nothing read them. This
makes capabilities authoritative, moves every size into one shared module, and
adds schema v2 (fixed 250G rancher / 300G longhorn, never --grow). Existing
machines stay v1 forever: schema is detected from the on-disk VG tag, so a v1
box stays v1 even when v2 is requested.

Proven on real VMs, not just unit tests: all four topologies installed and had
their layouts read back off the machines; markers in /home, /srv,
/var/lib/longhorn and /var/lib/rancher survived reinstall; and a 4-node cluster
formed, took real data, and had all three servers rolled one at a time through
evacuate / wipe / reinstall / rejoin with checksums verified before and after
each roll. Drill: 10/10, evidence in migration/drill-evidence/.

Production defects the drill found, none of which a unit test could reach:

- sshOpts() capped every operation at 30s while drainNode asked kubectl for
  --timeout=15m, so the transport killed the drain after evicting most pods and
  returned a transcript that read like success. `labctl app k3s evacuate` could
  never have drained a real node.
- generateAgentConfig put node-role.kubernetes.io/worker in the kubelet's
  node-label list, which NodeRestriction rejects, so no agent installed through
  K3sModule could start. systemd reported only "did not take the steps required
  by its unit configuration".
- toOpContext built K3sConfig by enumerating three keys and silently dropped
  the rest, so the k3s version pin did nothing and --allow-single-replica was a
  no-op that claimed to override a data-loss guard.
- The Longhorn disk annotation was mangled by shell quoting; with
  createDefaultDiskLabeledNodes the node then gets no disk at all, joins, goes
  Ready, and silently hosts no replica.
- evacuate drained before evicting, which blocks on Longhorn's PDBs and would
  destroy a single-replica volume's only source.
- etcd member ids were parsed from JSON, losing uint64 precision and emitting
  decimal where `member remove` needs hex -- at the moment a node is stopped
  and about to be wiped.
- get.k3s.io installs latest, two minor versions ahead of the fleet, so a
  reinstalled node would rejoin on a newer k3s than its peers and roll an
  unplanned two-version control-plane upgrade. K3sConfig.k3sVersion now pins it.
- `labctl app k3s install --role x` mapped anything that was not "worker" to
  "infra", so the runbook's own `--role k8s-combo` would have installed a
  different role with different disk expectations and no warning.

Also: /var/lib/longhorn/replicas must never be deleted, only its contents, or
every replica placed on the node dies on a non-recursive mkdir -- for ever,
while the node reports Ready, Schedulable and healthy.

etcd is now in the kickstart's package set for k3s server roles, because
`k3s etcdctl` is not a command and a member that needs to recover its own
membership has no internet.

542 unit tests / 39 files.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

bastion/tests/integration/helpers/pxe-vm.ts

@@ -28,6 +28,13 @@ export interface PxeVmConfig {
   vcpus: number;
   diskSize: number;     // GB
   network: string;      // libvirt network name
+  /**
+   * Serial console TCP port. Defaults to 4555 for backwards compatibility with
+   * the single-VM tests, but it MUST be unique per concurrently-running VM:
+   * qemu fails with "Failed to find an available port: Address already in use"
+   * and the domain never starts.
+   */
+  serialPort?: number;
   arch?: "x86_64" | "aarch64";
   /**
    * Extra NICs enumerated BEFORE the PXE NIC, on a network with no route to
@@ -86,8 +93,8 @@ export function createPxeVm(config: PxeVmConfig): void {
     // Graphics for debugging (VNC, connect with virt-viewer if needed)
     "--graphics=vnc,listen=127.0.0.1",
     // Serial console via TCP — allows exec without network/SSH
-    // Connect: socat - TCP:127.0.0.1:4555
-    "--serial=tcp,host=127.0.0.1:4555,mode=bind,protocol=telnet",
+    // Connect: socat - TCP:127.0.0.1:<serialPort>
+    `--serial=tcp,host=127.0.0.1:${config.serialPort ?? 4555},mode=bind,protocol=telnet`,
   ];
 
   if (arch === "aarch64") {
@@ -96,7 +103,7 @@ export function createPxeVm(config: PxeVmConfig): void {
 
   log(`Running: virt-install --name=${config.name} --boot=uefi,network ...`);
   run(virtInstallArgs.join(" "), { timeout: 30_000 });
-  log(`PXE VM ${config.name} created (serial: telnet 127.0.0.1 4555)`);
+  log(`PXE VM ${config.name} created (serial: telnet 127.0.0.1 ${config.serialPort ?? 4555})`);
 }
 
 /** Destroy a PXE VM and clean up its disk. */