Feature Request: Support Multi-Host Cluster Virtual Mode for Enhanced High Availability

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Currently, K3K's virtual mode creates virtual clusters confined to a single host Kubernetes cluster. While this provides isolation, it limits high availability because the entire virtual cluster depends on the availability of its single host cluster. If the host cluster experiences downtime, all virtual clusters within it become unavailable—even if other healthy host clusters exist in the infrastructure. This single-point-of-failure constraint reduces the resilience of virtual clusters in production scenarios where cross-cluster fault tolerance is critical. Furthermore, for applications that are designed to manage multiple clusters themselves (e.g., Rancher Manager), deploying them within a virtual cluster that is itself limited to one host cluster creates an architectural constraint and reduces the application's own resilience.