[Feature Request] Add per-subagent observability (model, effort) to /agents Running tab and agent JSON output

Bug Description
Subagent observability gap. There's no way to see live per-subagent model and effort without blocking. /agents Running tab queues behind the busy main loop and doesn't show model/effort columns. claude agents runs out-of-process but explicitly excludes in-session subagents. Requests: (1) add model + effort columns to the /agents Running tab, (2) include in-session subagents in the out-of-process agent view (or expose them via claude agents --json), (3) add model/effort to that JSON output.

Environment Info

• Platform: darwin
• Terminal: vscode
• Version: 2.1.193
• Feedback ID: c96c8d57-84d7-41c3-b447-fe6987c921be

Errors

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