[Bug] TUI rendering corruption in Tmux: overlapping text output and screen state mismatch

Bug Description
I am running claude in Tmux 3.5a in ghostyy on a macbook. Text output is consistently getting messed up, with TUI elements rendering over the top of each other. It is like the internal representation of the screen no longer matches. I do not need to resize the pane for this to happen. This is making claude impossible to use - as I cannot monitor what it is doing.

This is an innocuous example where the input is rendered twice. It often corrupts the entire screen.
<img width="1250" height="288" alt="Image" src="https://github.com/user-attachments/assets/61bde6d8-5826-46f0-9355-a84a111f8ee6" />

Environment Info

• Platform: darwin
• Terminal: tmux
• Version: 2.1.169
• Feedback ID: ee3b8f15-64bc-4f73-bfe8-b77b63da612a

Errors

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