Harden the public endpoints.ValidateEndpoints guard used before StackRox integrations connect to…

Harden the public endpoints.ValidateEndpoints guard used before StackRox integrations connect to…: a task in MiMo-V2.6-RL-oss: Agentic RL Environments (MiMo RL release). Harden the public endpoints.ValidateEndpoints guard used before StackRox integrations connect to user-supplied services. The…