[Bug] Terminal transcript duplicated on window resize in TUI renderer

Bug Description
Existing transcript content gets duplicated on terminal resize. Every
resize multiplies the visible messages — the count compounds quickly
with each resize (roughly exponentially), and the session becomes
unusable almost immediately, not gradually. No typing required; just
resizing the window or any layout reflow triggers it.

Version: 2.1.119
OS: macOS 26 (Darwin 25.4.0)

Already ruled out:

• Empty ~/.claude/settings.json ({})
• No hooks configured
• MCP servers disabled (including xcode MCP)
• Multiple terminal apps
• Downgrade and re-upgrade to latest
• Fresh sessions with no history

Filed a previous report yesterday, still reproing on 2.1.119. Looks
like a redraw/reflow bug in the TUI renderer triggered by SIGWINCH /
resize events. Happy to attach /debug logs or a screen recording if
useful.

Environment Info

• Platform: darwin
• Terminal: vscode
• Version: 2.1.119
• Feedback ID: 12c87e14-c6e2-4bfe-8380-c23d5938e9dc

Errors

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<img width="673" height="410" alt="Image" src="https://github.com/user-attachments/assets/44358d39-f465-4727-bfe6-e7c7ecbcefaf" />