"Jump to bottom ↓" included in text selection/copy in fullscreen mode

Description

When selecting text in the terminal output and copying (Cmd+C), the "Jump to bottom ↓" UI element is included in the copied text. This pollutes the clipboard with UI chrome that shouldn't be part of the selection.

Steps to reproduce

1. Run Claude Code with flicker-free alt-screen rendering enabled (CLAUDE_CODE_NO_FLICKER=1)
2. Scroll up in the output
3. Select any text with mouse
4. Copy with Cmd+C
5. Paste — "Jump to bottom ↓" is included in the pasted text

Expected behavior

The "Jump to bottom ↓" button should be excluded from text selection, e.g. via CSS user-select: none or equivalent terminal rendering approach.

Environment

• Claude Code version: 2.1.96
• Rendering: flicker-free alt-screen (CLAUDE_CODE_NO_FLICKER=1)
• Terminals: iTerm2, tmux (reproduces in both)
• OS: macOS 15.4 (Darwin 25.4.0)

Notes

This does not appear to be terminal-specific since it reproduces across both iTerm2 and tmux. Likely in the alt-screen renderer's "Jump to bottom" overlay.