agent-platform release v4.76.1

A node drain no longer waits on the single-replica components’ budgets. The PodDisruptionBudgets of muster, klaus-gateway, agent-manager, muster-valkey and the kagent controller were minAvailable: 1 on one replica, which refuses every eviction: a cluster upgrade rolling its machines waited for each drain’s timeout. They are maxUnavailable: 1, so a drain evicts the pod and goes on. Karpenter’s consolidation stays away from those pods through their karpenter.sh/do-not-disrupt annotation (giantswarm/agent-platform#431), not through the budget. muster and klaus-gateway get minAvailable: "" next to it to clear their charts’ default of 1, and the kagent controller keeps its chart’s own default. A platform Postgres with postgres.instances: 1 renders enablePDB: false, because the operator’s budget on a lone primary has no replica to switch over to; two or more instances keep the operator’s budgets and its switchover on drain.