feat(ansible): parameterise target groups so prod reuses the roles unchanged (R-ENV-02)

roles/k3s_server, roles/cilium and every node-host playbook hardcoded the dev group
names k3s_primary/k3s_secondary/k3s_servers, so the prod inventory groups could not be
selected at all. That broke the R-ENV-02 promise that prod reuses the SAME roles, and
blocked PROD-PROVISIONING.md §6 outright.

TWO KNOBS, deliberately separate — Ansible templates a play's `hosts:` BEFORE any host
context exists, so group_vars is unreadable there, while roles run WITH host context:
  * which hosts a play RUNS ON — k3s_hosts, k3s_primary_hosts/k3s_secondary_hosts
    (k3s.yml's split), vpn_egress_gateway_hosts; each `| default(<dev group>)`, set by -e
    only. Follows node-health.yml's established `<name>_hosts | default(dev)` pattern.
  * which group a ROLE means by "my primary"/"my servers" — k3s_primary_group,
    k3s_servers_group in group_vars/all.yml (dev), overridden in group_vars/k3s_prod.
    Follows the k3s_api_host convention already in this repo. No per-run flag.

DEV IS UNCHANGED — the key evidence. --list-hosts/--list-tasks/--syntax-check captured
for all 9 playbooks at HEAD and after: sorted host lists IDENTICAL for all 9, same
primary/secondary split, same 6-play site.yml. (Raw --list-hosts PRINT ORDER varies run
to run; proven to be Ansible's own set ordering by running UNMODIFIED HEAD cilium.yml
four times -> 3,1,2 / 1,3,2 / 1,2,3 / 1,2,3. Hence sorted comparison.) --list-tasks
differs in exactly two files, only by added TAGS annotations and one new assert; no task
reordered, renamed or removed. Var resolution verified per environment with -c local:
dev -> k3s_primary/192.168.1.50/sans .50,.49,127.0.0.1,.51,.52; prod ->
k3s_prod_primary/192.168.2.10/vip .9/sans .10,.9,127.0.0.1,.11,.12.

BREAKS THE SMARTMONTOOLS CIRCULAR DEPENDENCY. node_baseline tasks are now tagged
packages/system/disks, so the package install can run alone:
  ansible-playbook playbooks/node-baseline.yml -e k3s_hosts=k3s_prod --tags packages
Skipping is the guard — no disks-tagged task is selected, so the
BLOCKED-pending-disk-decision paths are never templated, let alone passed to mkfs.
Belt-and-braces, a new disks-tagged assert fires first in a FULL run and names §2
explicitly instead of failing obscurely at mkfs. `tags: never` was deliberately NOT used
(it would change the default run).

FOOTGUN FOUND AND FIXED: roles/cilium, cluster_verify and flux_bootstrap all hardcoded
.cache/dev.kubeconfig — the exact file infra/devcontainer/dev.sh exports as $KUBECONFIG.
Once prod became targetable, a prod cilium/verify run would have SILENTLY OVERWRITTEN it,
leaving the operator's kubectl quietly answering from PROD. Now cluster_kubeconfig_name
(dev.kubeconfig -> prod.kubeconfig). Dev path byte-identical.

KNOWN, DOCUMENTED, NOT FIXED HERE: flux-bootstrap.yml retargets but roles/flux_bootstrap
shells out to bootstrap/flux/bootstrap.sh with a hardcoded --path=clusters/dev — a
bootstrap/ subtree change, not a target-group change (§6, cross-referenced to §7).
vpn.egress.gateway.yml is parameterised but prod has no egress group yet and would need
its own vaulted PIA credentials. --check against prod is still impossible until the prod
vault exists — even the packages-only run needs it.

Nothing was run against the dev cluster: --list-hosts/--list-tasks/--syntax-check, plus
debug/assert with -c local, only.

Serves: R-ENV-01, R-ENV-02, R-ENV-03. Task: T-7.1.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

infra/ansible/roles/k3s_server/tasks/main.yml

@@ -121,19 +121,23 @@
 # contained — delegate_to still reaches the primary even when it isn't a play
 # target, so the join no longer depends on a fact an earlier play had to set.
 # T-1.5 finding F2 (see DECISIONS-LOG.md).
+#
+# "The primary" is resolved through k3s_primary_group (group_vars: `k3s_primary` for
+# dev, `k3s_prod_primary` for prod), never a literal group name — so a prod secondary
+# delegates to the PROD primary using this same role, unchanged (R-ENV-02).
 - name: Fetch the k3s node-token directly from the primary (secondary)
   ansible.builtin.slurp:
     src: /var/lib/rancher/k3s/server/token
-  delegate_to: "{{ groups['k3s_primary'][0] }}"
+  delegate_to: "{{ groups[k3s_primary_group][0] }}"
   register: k3s_primary_token_raw
   when:
     - k3s_server_mode == 'secondary'
-    - hostvars[groups['k3s_primary'][0]].k3s_node_token is not defined
+    - hostvars[groups[k3s_primary_group][0]].k3s_node_token is not defined
 
 - name: Resolve the join token (secondary)
   ansible.builtin.set_fact:
     k3s_join_token: >-
-      {{ hostvars[groups['k3s_primary'][0]].k3s_node_token
+      {{ hostvars[groups[k3s_primary_group][0]].k3s_node_token
          | default(k3s_primary_token_raw.content | b64decode | trim, true) }}
   when: k3s_server_mode == 'secondary'