[Feature]: Open Codex sub-agent rows to inspect live progress

[parkavenue9639]

Problem or use case

Orca can surface Codex internal sub-agents as nested sidebar rows, but users cannot open a child row to inspect that child session directly.

This is a high-frequency workflow when a parent Codex session dynamically spawns, parks, resumes, or completes multiple internal workers. The parent terminal alone does not make it easy to follow each child independently, distinguish live reasoning and tool activity, or confirm that the final child result returned to the parent.

This is a focused child scope of #8251 and follows the lifecycle visibility added by #9637. It does not cover cross-worktree orchestration relationships or worker deduplication.

Proposed solution

Make Codex internal sub-agent rows clickable in both full and compact sidebar views.

• Open the selected provider-assigned child session in a non-modal, read-only progress view.
• Render only the selected child history and live activity, excluding inherited parent turns and sibling transcripts.
• Keep progress live across dynamic spawn, waiting, resume, interruption, completion, disappearance, and later child creation.
• Preserve parent terminal focus while showing which child is selected.
• Route transcript reads through the owning local, folder-workspace, managed-runtime, or SSH context, and fail closed when ownership is ambiguous.

Acceptance criteria:

1. Clicking a live Codex child row opens that child progress view without switching the parent terminal.
2. Reasoning, tool activity, lifecycle changes, and the final result update live.
3. Parent and sibling conversation history does not appear in the child view, including sessions created with full-history forks.
4. Dynamically created and completed children appear and disappear independently without stale running states.
5. Local worktrees, folder workspaces, managed runtimes, and supported SSH-owned sessions preserve the correct transcript authority.
6. The surface remains read-only and does not introduce child prompt, interrupt, or PTY control paths.

Alternatives or additional context

Opening Codex rollout JSONL manually is possible but is not a practical live workflow and bypasses Orca host-routing and session ownership rules.

Related umbrella: #8251

Implementation: #12311

[optimus-brian]

Same gap exists for Claude Code's Workflow tool (its multi-agent orchestration), not just Codex.

When a Claude Code agent runs a workflow, the sub-agents execute in the background. In the Claude CLI you can inspect their live progress via /workflows, but in Orca there's no equivalent: the desktop UI shows only "Agent is working", and on the iOS app there's nothing at all. No rows, no panes, no entry in Agent activity.

Concretely, in a session where the agent made 3 Workflow calls (confirmed in the session .jsonl), the orchestration ran fine and produced correct results, but from Orca's side it was completely opaque, you can't tell how many sub-agents ran, which models they used, or where they are. For anyone running autonomous agents on a headless/remote host this is the main blind spot: the work happens, you just can't watch or steer it.

Would be great if surfacing sub-agent rows here also covered Claude Code workflow sub-agents (ideally by consuming the same /workflows progress stream the CLI already exposes).