fix(vpn-ingress): content-hash the peer register, or a merged peer never reaches the tunnel

The operator enrolled a phone, merged the peer, and `wg show` listed none.
Measured on prod 2026-10-06 with the peer already on main:

  live wg-peers ConfigMap, active AllowedIPs .. 0
  DaemonSet volume reference ................. configMap.name: wg-peers (FIXED)
  DaemonSet generation/observedGeneration .... 1 / 1   (never rolled)
  init container, all three pods ............. "0 peer(s)"

Part of it was just the 10m reconcile interval. The defect is the fixed name:
Flux updates a fixed-name ConfigMap IN PLACE, so the pod template is
byte-identical, so no rollout is triggered -- and the init container assembles
wg0.conf ONCE at pod start into a tmpfs, so the running tunnel keeps the old
peer list indefinitely. Adding or revoking a peer had no effect until something
unrelated restarted the pods. For a REVOCATION that is a security defect, not
an inconvenience: delete a stanza, see a green PR, device keeps working.

The runbook and README both claimed "PR -> merge -> Flux rolls the DaemonSet".
Never true. And this repo already documents the fix, in a file I had read --
runbooks/kustomization.yaml: "The generated name carries kustomize's content
hash, so editing any runbook rolls the server automatically and a stale
projection is impossible."

So: peers.yaml (inline ConfigMap) -> peers.conf (plain file) + a
configMapGenerator. The operator's enrolled peer is carried across verbatim.
Every line is WireGuard config and `#` is a legal comment there, so the
documentation now lives inside the file that is actually mounted.

`namespace: vpn-ingress` on the kustomization is REQUIRED, not tidiness: a
generated ConfigMap inherits no namespace, everything else here declares
vpn-ingress, and kustomize's nameReference will not rewrite across a namespace
boundary -- without it the build mounts the unhashed name and the pods wedge on
a missing volume. Caught only by building the output and reading the volumes.

new-peer.sh: PEERS_FILE repointed, and a missing register is now FATAL rather
than skipped -- the old `[ -r "$PEERS_FILE" ] && grep ...` guard meant that
after the rename the only symptom would have been duplicate detection quietly
never firing again. Stale peers.yaml references swept from six files including
the script's own user-facing output.

Verified: the DaemonSet now mounts wg-peers-m9kcckcb5t; the hash tracks content
(edit -> dgg7ht9c74 -> restore -> m9kcckcb5t); the enrolled peer is byte-identical
to main's; and `new-peer.sh dupe 2` is now correctly refused by the operator's
real allocation.

No sensitive paths; merges on a green gate.

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

platform/vpn-ingress/kustomization.yaml

@@ -11,10 +11,16 @@
 # NOT in platform/kustomization.yaml — see clusters/base/vpn-ingress.yaml.
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
+# REQUIRED for the configMapGenerator below to be wired up at all, not merely tidy. A generated
+# ConfigMap inherits NO namespace, every other object here declares `vpn-ingress`, and kustomize's
+# nameReference transformer will not rewrite a reference across a namespace boundary — so without
+# this the DaemonSet keeps mounting the unhashed name `wg-peers`, which does not exist, and the
+# pods wedge on a missing volume. Verified by building it both ways (kustomize v5.8.1).
+# Same placement as runbooks/kustomization.yaml, which uses `namespace: runbooks` for its own
+# content generator.
+namespace: vpn-ingress
 resources:
   - namespace.yaml
-  # The peer register: which devices may dial in. PLAINTEXT and reviewable on purpose (see the file).
-  - peers.yaml
   # The listener itself: hostNetwork DaemonSet, udp/51820 on every node.
   - daemonset.yaml
   # Namespace default-deny baseline. NOTE: does NOT constrain the hostNetwork DaemonSet — the file
@@ -38,3 +44,26 @@ resources:
 # hands Flux the raw ciphertext, the Secret APPLIES CLEANLY full of ENC[...], and nothing in any
 # Flux condition looks wrong. The init container's `wg pubkey` guard exists partly to turn exactly
 # that into a named error rather than a silently non-working tunnel.
+
+# ── THE PEER REGISTER, as a CONTENT-HASHED ConfigMap ─────────────────────────────────────────
+# peers.conf (plaintext, reviewable — see the file) becomes the `wg-peers` ConfigMap. It is a
+# GENERATOR, not a plain resource, and that distinction is load-bearing rather than stylistic:
+# kustomize appends a hash of the content to the generated name and rewrites the DaemonSet's
+# volume reference to match, so adding or revoking a peer changes the pod template and ROLLS THE
+# PODS automatically.
+#
+# A fixed-name ConfigMap (which is what this component shipped first) does not do that. Flux
+# updates it in place, the pod template is byte-identical, no rollout is triggered — and because
+# the init container assembles wg0.conf ONCE at pod start into a tmpfs, the running tunnel keeps
+# the old peer list indefinitely. Measured on prod 2026-10-06: a merged peer reached the
+# ConfigMap while `wg show` listed no peers and the DaemonSet still read generation=1, having
+# never rolled. The runbook's "PR -> merge -> Flux rolls the DaemonSet" was false until this.
+#
+# DO NOT set `disableNameSuffixHash` here. The hash IS the mechanism.
+configMapGenerator:
+  - name: wg-peers
+    files:
+      - peers.conf
+    options:
+      labels:
+        app.kubernetes.io/name: vpn-ingress