refactor(ci): move forgejo-runners from worker-1 to talos-cp-2

Schedule runners on az-b (talos-cp-2) which has more Longhorn storage
and breathing room (367Gi available vs worker-1's 369Gi but over-provisioned).

PVCs deleted and will recreate on new zone. Runners will re-register.

k8s/infra/forgejo-runner/values.yaml

@@ -49,10 +49,10 @@ tolerations:
     operator: Exists
     effect: NoSchedule
 
-# Pin to az-a (talos-cp-1) — sole Longhorn node; RWO PVCs (reg/dind cache) only
-# attach there.
+# Pin to az-b (talos-cp-2) — more Longhorn storage than az-a (worker-1 over-provisioned).
+# RWO PVCs will recreate on talos-cp-2 when nodeSelector changes.
 nodeSelector:
-  topology.kubernetes.io/zone: az-a
+  topology.kubernetes.io/zone: az-b
 
 # GC CronJob — prunes Docker images/volumes/build-cache and actcache across
 # ALL forgejo-runner pods. Only enable in default values (golang instance);