feat(cli): add sub-command 'arena llm' as proxy to kubectl-rbg

[diw-zw]

Summary

Adds a new llm subcommand to the arena CLI that proxies all arguments to the kubectl-rbg binary. This allows users to access LLM deployment management capabilities through a single unified entry point (arena llm ...) without merging the two tools' codebases or resolving dependency conflicts.

Motivation

kubectl-rbg provides LLM-related capabilities (service management, model management, benchmarking, etc.) as a separate CLI tool. Requiring users to remember and switch between two binaries degrades the user experience. This change unifies the entry point while keeping both tools independently maintainable.

Changes

• pkg/commands/llm/llm.go — new file; defines NewLLMCommand() which delegates to kubectl-rbg llm <args...> via os/exec, with stdin/stdout/stderr passthrough and a clear error message if kubectl-rbg is not found in $PATH
• pkg/commands/root.go — registers the new llm subcommand

Usage

# equivalent to: kubectl-rbg llm svc list
arena llm svc list

# equivalent to: kubectl-rbg llm --help
arena llm --help

[cheyang]

/lgtm
/approve

[google-oss-prow]

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This pull-request has been approved by: cheyang

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