chore(talos): move to v1.13.12

Fixes CVE-2026-99999 (ipv4: validate checksum_start before completing
checksum, CVSS 9.3). The nodes run 6.18.48-talos; the fix is in 6.18.57,
which v1.13.12 ships (siderolabs/pkgs@19e92dc).

Not applied to any node yet. Rollout is one node at a time: drain,
talosctl upgrade --image, wait for Ceph HEALTH_OK, starting with k8s-1.

Patch release within 1.13; Kubernetes stays v1.36.3. Schematic is
unchanged; factory installer manifest and ISO verified to exist for the
tag. talosctl checksum taken from the release's sha256sum.txt.

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

ci/images/k8s/Containerfile

@@ -1,6 +1,6 @@
 FROM alpine:3.24@sha256:294b683cb724975bec92580e1e685676bd4b50bda910ddb8c51d4cabeaec77e6
 
-ARG TALOS_VERSION=v1.13.10
+ARG TALOS_VERSION=v1.13.12
 ARG VELERO_VERSION=v1.16.0
 ARG KUBECTL_VERSION=v1.36.3
 ARG FLUX_VERSION=2.9.5
@@ -18,7 +18,7 @@ RUN apk add --no-cache \
 
 RUN curl -sfL -o /usr/local/bin/talosctl \
       "https://github.com/siderolabs/talos/releases/download/${TALOS_VERSION}/talosctl-linux-amd64" \
- && echo "28e9ccd9aebd690fa03d8cf2582221d87ea38b2a1704f411d75a03589c58f2aa  /usr/local/bin/talosctl" | sha256sum -c - \
+ && echo "4ce4218764c24d6a6bd561097199b60ed8619db073792fce5b7cfce7fa8d12fc  /usr/local/bin/talosctl" | sha256sum -c - \
  && chmod +x /usr/local/bin/talosctl
 
 RUN curl -sfL -o /usr/local/bin/kubectl \

ci/images/vmtest/Containerfile

@@ -14,7 +14,7 @@ FROM alpine:3.24@sha256:294b683cb724975bec92580e1e685676bd4b50bda910ddb8c51d4cab
 # kubernetes/talos/patches/cluster.yaml. The phase reads the version from that
 # file at run time and passes it to the provisioner; this pin only decides which
 # client talks to it.
-ARG TALOS_VERSION=v1.13.10
+ARG TALOS_VERSION=v1.13.12
 ARG KUBECTL_VERSION=v1.36.2
 ARG FLUX_VERSION=2.9.2
 ARG KOPIA_VERSION=0.23.1
@@ -49,7 +49,7 @@ RUN apk add --no-cache \
 
 RUN curl -sfL -o /usr/local/bin/talosctl \
       "https://github.com/siderolabs/talos/releases/download/${TALOS_VERSION}/talosctl-linux-amd64" \
- && echo "28e9ccd9aebd690fa03d8cf2582221d87ea38b2a1704f411d75a03589c58f2aa  /usr/local/bin/talosctl" | sha256sum -c - \
+ && echo "4ce4218764c24d6a6bd561097199b60ed8619db073792fce5b7cfce7fa8d12fc  /usr/local/bin/talosctl" | sha256sum -c - \
  && chmod +x /usr/local/bin/talosctl
 
 RUN curl -sfL -o /usr/local/bin/kubectl \

kubernetes/RUNBOOK-cold-rebuild.md

@@ -107,7 +107,7 @@ config, and the nodes are addressed by name.
 ## Step 1b — boot all three machines from install media
 
 ```
-https://factory.talos.dev/image/0f6fb8bd8bb53013e9743b7c7b099d96fb9c32fd2464ced32693c2dc0ea5feb9/v1.13.10/metal-amd64.iso
+https://factory.talos.dev/image/0f6fb8bd8bb53013e9743b7c7b099d96fb9c32fd2464ced32693c2dc0ea5feb9/v1.13.12/metal-amd64.iso
 ```
 
 Write it to a USB stick and boot each MS-01 from it. Each comes up in

kubernetes/talos/patches/cluster.yaml

@@ -24,7 +24,7 @@ machine:
   # The Kubernetes version is a separate decision, moved by
   # `talosctl upgrade-k8s`.
   install:
-    image: factory.talos.dev/metal-installer/0f6fb8bd8bb53013e9743b7c7b099d96fb9c32fd2464ced32693c2dc0ea5feb9:v1.13.10
+    image: factory.talos.dev/metal-installer/0f6fb8bd8bb53013e9743b7c7b099d96fb9c32fd2464ced32693c2dc0ea5feb9:v1.13.12
   features:
     rbac: true
     # stableHostname is NOT here: it is the v1alpha1 spelling of what the