[Feature]: Agents panel should also show CLI-delegated child agents (codex exec / opencode run / etc.), not only provider-native subagents #5479

Before submitting

• I searched existing issues and did not find a duplicate. ([Bug]: Desktop/web thread shows no sign of delegated CLI-agent work: silent while it runs, idle-looking when backgrounded, spontaneous wake after #5043 reports the same underlying gap as a pre-Agents-panel bug on the thread surface; this is a feature request scoped to the new Agents panel shipped in PR feat: native subagent & workflow observability #5219.)
• I included enough detail to reproduce or investigate.

Area

apps/web

Feature request

Render CLI-delegated child agents in the Agents panel, not only provider-native subagents.

PR #5219 ("native subagent & workflow observability", v0.0.32-nightly.20260806.1012) is a great step: Claude Code Task-tool spawns and Codex collab agents now show up in the Agents panel with model, tokens, tool count, and status. Thank you for this.

But a very common delegation shape is still invisible there: the primary agent spawning another vendor's agent CLI as a child process — e.g. a Claude thread running codex exec "…" or opencode run "…" --auto --format json through its Bash tool (foreground or backgrounded). Multi-vendor routing like this is how many of us pick a cheap/fast model per task while keeping one conversation.

Repro (today, on v0.0.32-nightly.20260806.1012):

1. In a Claude thread, spawn a native subagent via the Task tool → it appears in the Agents panel with full attribution. ✅
2. In the same thread, ask the agent to run opencode run "say hi" --auto --format json or codex exec "say hi" as a background Bash command → the child agent runs to completion but never appears in the Agents panel; the only trace is the generic running-task line in the transcript. ❌

Both are "my thread is running a fleet," but only one is observable in the panel.

Suggested directions (either would help):

• Heuristic attribution: recognize well-known agent CLIs (codex exec, opencode run, claude -p, grok, cursor-agent, …) in Bash/exec tool events and render them as panel members with elapsed time and status derived from the process/tool lifecycle.
• Explicit annotation: a documented way for the primary agent (or a wrapper script) to declare "this command is a child agent: vendor, model, task label" so the panel can render it first-class — this seems to fit the Orchestrator v2 schema alignment mentioned in feat: native subagent & workflow observability #5219.

Related: #5043 (same gap reported on the thread/transcript surface before the Agents panel existed).