chore(ci): run pipelines on ci-k8s:2026-09-08

The tag build-ci-images published from #827 (pipeline 8573): talosctl
v1.13.9, kubectl v1.36.3, flux 2.9.5. Six references moved from
2026-08-10.

Refs #426

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

.woodpecker/alert-monitor.yml

@@ -42,7 +42,7 @@ when:
 
 steps:
   - name: fetch-alerts
-    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-08-10
+    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-09-08
     environment:
       SOPS_AGE_KEY:
         from_secret: sops_age_key

.woodpecker/ci-manifests-test.yml

@@ -60,7 +60,7 @@ steps:
   # run that never touched them. Tracked in #461.
   - name: kustomize-build
     depends_on: [] # see note above `steps:`
-    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-08-10
+    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-09-08
     commands:
       - |
         set -eu
@@ -246,7 +246,7 @@ steps:
   # this step fails permanently on its own documentation.
   - name: no-digest-pins
     depends_on: [] # see note above `steps:`
-    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-08-10
+    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-09-08
     commands:
       - |
         set -eu

.woodpecker/e2e-test.yml

@@ -4,7 +4,7 @@ when:
 
 steps:
   - name: e2e
-    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-08-10
+    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-09-08
     environment:
       SOPS_AGE_KEY:
         from_secret: sops_age_key

.woodpecker/e2e.yml

@@ -31,7 +31,7 @@ steps:
       - sh scripts/ci/test-model-selection.sh
 
   - name: e2e-test
-    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-08-10
+    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-09-08
     environment:
       SOPS_AGE_KEY:
         from_secret: sops_age_key

.woodpecker/issue-fix.yml

@@ -49,7 +49,7 @@ steps:
     # (the issue-pick logic needs jq, which only the ci-claude image has);
     # minting a 1h read-only token per run is cheap. Degrades to
     # snapshot-only if the ci-diagnostics ServiceAccount isn't reconciled.
-    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-08-10
+    image: gitea.renner.uno/gitea_admin/ci-k8s:2026-09-08
     environment:
       SOPS_AGE_KEY:
         from_secret: sops_age_key