Harden the URL rewriting performed by the client-go transport used to talk to Clusternet's shadow API.

Harden the URL rewriting performed by the client-go transport used to talk to Clusternet's shadow API.: a task in MiMo-V2.6-RL-oss: Agentic RL Environments (MiMo RL release). The transport receives ordinary Kubernetes API requests and forwards them through the hub's configured base path, but the…