tui: /copy fails when transcript contains NUL characters

[heymaaz]

Description

/copy fails with Failed to copy session transcript when a session transcript includes NUL characters from shell output. OpenTUI rejects clipboard text containing NUL characters before it reaches an otherwise healthy host clipboard.

OpenCode version

0.0.0-beta-17898

Steps to reproduce

1. Create a session with shell tool output containing NUL characters.
2. Run /copy in that session.
3. Observe the error toast and unchanged clipboard.

Expected: the supported transcript text is copied after omitting NUL characters.

Actual: the entire clipboard write fails with Failed to copy session transcript.

Screenshot and/or share link

Screen.Recording.2026-08-22.at.4.44.08.PM.mov

Operating System

macOS (Darwin 25.6.0, arm64)

Terminal

Ghostty 1.3.1