Subagent transcript view status line shows parent session model, not the subagent's model override

Bug

When a subagent is launched via the Agent tool with an explicit model override (e.g. model: "opus"), the status line at the bottom of the subagent's chat/transcript view still displays the parent session's model (e.g. fable-5), not the model the subagent actually runs on.

Why it matters

The user instructed that all subagents run on Opus. The agent was launched with model: "opus" and its transcript JSONL confirms every request executed on "model":"claude-opus-5" — but the subagent view's status line kept showing fable-5 (the parent session's model). The user reasonably concluded the instruction was being ignored and killed the agent repeatedly (4 kills across two tasks), losing significant work and tokens.

Expected

The status line (and any model label) in a subagent's view should show the subagent's effective model.

Actual

It shows the parent session's model. The user reports the label does normally update when switching models in a regular session, which made the stale label extra convincing.

Repro

1. Run a session on one model (here: fable-5, in a background job).
2. Launch a general-purpose subagent via the Agent tool with model: "opus".
3. Open the subagent's view from the task list (Enter to view).
4. Status line shows the parent model; meanwhile grep '"model"' <task output jsonl> shows only claude-opus-5.

Environment

• Claude Code 2.1.283, macOS (Darwin 25.5.0), background job session, parent model claude-fable-5, subagent claude-opus-5.