Fullscreen (alternate-screen) mode breaks terminal copy — can't select/copy login URL

What happens

While Claude Code runs in fullscreen (alternate-screen) mode, terminal text selection/copy stops working. I could not select and copy a login URL printed in the console in order to paste it into a browser, which blocked the authentication flow.

Impact

Any auth/login flow that prints a URL to be copied becomes unusable while in fullscreen mode — there is no way to get the URL out of the terminal.

Steps to reproduce

1. Run Claude Code with the fullscreen / alternate-screen renderer enabled.
2. Trigger a flow that prints a URL to copy (e.g. an auth/login URL).
3. Try to select the URL with the mouse to copy it.
4. Selection/copy does not work.

Environment

• Linux terminal over SSH, on a remote node (staging).
• Claude Code fullscreen / alternate-screen renderer enabled.

Likely cause

The TUI's mouse tracking / alternate-screen capture intercepts the terminal's native selection, so normal click-drag no longer selects text.

Suggested fix

Make copy work in fullscreen mode — e.g. respect Shift-modified selection, add OSC 52 clipboard support, or expose a copy affordance for printed URLs — and/or render auth URLs in a region that is copyable without leaving fullscreen.

Workaround (for reference)

Holding Shift while dragging bypasses the app's mouse capture in most terminals (then Ctrl+Shift+C), or /tui default exits fullscreen before copying.