Backend: AgentRegistryService gains findByApplicationAndEnvironment()
and environment-aware addGroupCommandWithReplies() overload.
AgentCommandController and ApplicationConfigController accept optional
environment query parameter. When set, commands only target agents in
that environment. Backward compatible — null means all environments.
Frontend: All command mutations (config update, route control, traced
processors, tap config, route recording) now pass selectedEnv to the
backend via query parameter.
Prevents cross-environment command leakage — e.g., updating config for
prod no longer pushes to dev agents.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>