fix(multus): cni-plugins-installer to containernetworking/plugins v1.9.1

Point the installer at cni-plugins:2026-10-05, built from #1140
(plugins v1.5.1 -> v1.9.1). Version comments updated in the installer
and cni-dhcp-daemon.

Refs: REN-722
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

kubernetes/infrastructure/multus/cni-dhcp-daemon.yaml

@@ -37,7 +37,7 @@
 # or rolling updates will collide again on a single reservation.
 #
 # The dhcp binary ships from the sibling cni-plugins-installer DaemonSet
-# (containernetworking/plugins v1.5.1, whole tarball extracted). Keep the
+# (containernetworking/plugins v1.9.1, whole tarball extracted). Keep the
 # version pins in step.
 apiVersion: apps/v1
 kind: DaemonSet

kubernetes/infrastructure/multus/cni-plugins-installer.yaml

@@ -10,7 +10,7 @@
 # rather than an extra initContainer in the vendored multus manifest so
 # upstream multus updates can be re-vendored cleanly.
 #
-# Pinned to containernetworking/plugins v1.5.1 — bump together with the
+# Pinned to containernetworking/plugins v1.9.1 — bump together with the
 # multus version when refreshing upstream pins.
 apiVersion: apps/v1
 kind: DaemonSet
@@ -74,7 +74,7 @@ spec:
           # No imagePullSecret: the ghcr namespace is private and its credential
           # is in machine.registries too, because a Secret would have to come
           # from OpenBao, which needs Ceph, which needs these binaries.
-          image: gitea.renner.uno/konairius/cni-plugins:2026-09-04
+          image: gitea.renner.uno/konairius/cni-plugins:2026-10-05
           command:
             - sh
             - -c