[TUI] Cursor disappears and keyboard navigation breaks in agents tab after running subagents

Description

After using subagents (spawned via the Agent tool), two TUI issues persist until Claude Code is restarted:

1. Cursor indicator (|) disappears in the main input prompt — the cursor is no longer visible, making it hard to know where you're typing.
2. Keyboard navigation stops working in the Agents tab — after switching to the agents tab, arrow keys and keyboard shortcuts no longer respond. The only way to select a session is with the mouse.

Steps to Reproduce

1. Start a conversation and spawn one or more subagents (e.g., via the Agent tool with subagent_type: "Explore" or similar).
2. Wait for the subagent to complete.
3. Return to the main input — cursor | is no longer visible.
4. Switch to the Agents tab — keyboard navigation is unresponsive.

Expected Behavior

• Terminal state (cursor visibility, raw mode) should be fully restored after a subagent finishes.
• The Agents tab should retain keyboard focus and allow navigation with arrow keys.

Workaround

• For the cursor issue: running reset or stty sane in the terminal restores the cursor temporarily.
• For keyboard navigation: no reliable workaround found — mouse selection is required.

Environment

• OS: Windows 11 Pro 10.0.26200
• Shell: PowerShell 5.1
• Claude Code version: 2.1.168