[BUG] Fullscreen TUI: footer navigation (Left/Right arrow) re-enables mouse capture, ignoring CLAUDE_CODE_DISABLE_MOUSE=1

Version: 2.1.198
Platform: Linux (Debian 12), bash
Renderer: fullscreen TUI ("tui": "fullscreen" in ~/.claude/settings.json)
Config: export CLAUDE_CODE_DISABLE_MOUSE=1 set in .bashrc (verified present in the session's environment)

Steps to reproduce

1. Launch claude with CLAUDE_CODE_DISABLE_MOUSE=1 in the environment — mouse capture is correctly disabled and native terminal text selection works.
2. With an empty input box, press Left arrow — navigates to the footer/status area (footer:previous).
3. Press Right arrow — returns to the chat input (footer:next).

Expected

Mouse capture stays disabled; CLAUDE_CODE_DISABLE_MOUSE=1 keeps being honored.

Actual

After returning from the footer, mouse capture is re-enabled (clicks/drag/wheel are captured by Claude Code again and native terminal selection stops working). The CLAUDE_CODE_DISABLE_MOUSE setting is ignored for the rest of the session.

Notes

• Reproduces consistently with just the Left-then-Right arrow round-trip.
• Possibly related but distinct: #70724 (wheel navigates history with DISABLE_MOUSE on Windows), #71826 (native selection broken by mouse capture on macOS). Neither covers the footer round-trip re-arming capture.