Arrow key navigation trapped in subagent panel (can't return to chat input)

Description

When subagent panels are open at the bottom of a Claude Code session, pressing the down arrow to enter/browse a subagent panel works fine. However, pressing up arrow to return focus to the main chat input area does not work — focus remains trapped in the subagent panel with no way to navigate back to the chat input to continue typing.

Steps to Reproduce

1. Start a Claude Code session that spawns subagents (e.g., using Agent tool or team workflows)
2. Subagent panels appear at the bottom of the terminal
3. Press down arrow to navigate into a subagent panel
4. Press up arrow to try to return to the main chat input
5. Expected: Focus returns to the chat input area
6. Actual: Focus stays trapped in the subagent panel — cannot return to the chat input

Environment

• Claude Code version: 2.1.83
• Platform: Windows (WSL2)
• Terminal: Windows Terminal

Related Issues

• #16608 — Arrow key looping between chats in claude -r (closed)
• #26377 — Resume menu arrow navigation causes pointer flicker (closed, dup of #16608)

Those issues cover arrow key problems in the resume picker. This bug is different — it occurs during a live session when navigating between the main chat and subagent panels.

Workaround

None known — currently requires restarting the session.