[Bug]: emojis rendered inside tmux cause first characters of next line to start at end of current line

Start by reproducing the emoji-width mismatch on Windows with tmux and the pi TUI, using the !printf example in the issue. Inspect WaveTerm's layout and width engine to find where the crown emoji is treated as one column. Done means text no longer overlaps or wraps incorrectly in tmux while preserving correct rendering outside tmux.

Current Behavior

Experiment running a temporary tmux server with debug logging returned:
utf8proc_wcwidth(1F451) returned 2

This is a classic multiplexer desync bug:

1. Tmux thinks 👑 is 2 columns wide. (Correct)
2. Pi TUI thinks 👑 is 2 columns wide. (Correct)
3. WaveTerm's layout/width engine thinks 👑 is 1 column wide, but its font renders the glyph across 2 columns
   anyway. (Incorrect)

Why this causes chaos:

• Directly outside tmux: There is no multiplexer virtual grid to sync. Node.js outputs sequential bytes,
  WaveTerm places them next to each other, and you only see a minor, imperceptible 1-column layout shift (like a
  box border being slightly short). No overlap, looks fine.
• Inside tmux: Tmux maintains a strict virtual grid buffer and optimizes redraws. Because WaveTerm's width
  engine and tmux's width engine disagree, tmux's optimized cursor updates place characters directly on top of
  the second half of the emoji glyph, causing overlapping text and chaotic wrapped lines!

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How to Fix (WaveTerm Settings on your Host):

Open WaveTerm's settings tab (Cmd + , or Ctrl + , or click the gear icon):

1. Unicode Version: Set to 11 or higher (optimally 15).
2. East Asian Ambiguous: Toggle the setting to treat ambiguous-width characters as double-width (2 columns).
3. Font: Ensure you're using a strictly monospaced font with correct emoji width support (e.g., JetBrains Mono,
   Fira Code, Hack, or SF Mono).

Expected Behavior

print the following using !printf to the pi TUI while in tmux:

1. Tmux thinks 👑 is 2 columns wide. (Correct)
2. Pi TUI thinks 👑 is 2 columns wide. (Correct)
3. WaveTerm's layout/width engine thinks 👑 is 1 column wide, but its font renders the glyph across 2 columns
   anyway. (Incorrect)

It will render as:

print the following using !printf to the pi TUI while in tmux:

 1. Tmux thinks 👑 is 2 columns wide. (Correct)
2. Pi TUI thinks 👑 is 2 columns wide. (Correct)                                                                                                              3
. WaveTerm's layout/width engine thinks 👑 is 1 column wide, but its font renders the glyph across 2 columns
    anyway. (Incorrect)

Steps To Reproduce

print the following using !printf to the pi TUI while in tmux:

1. Tmux thinks 👑 is 2 columns wide. (Correct)
2. Pi TUI thinks 👑 is 2 columns wide. (Correct)
3. WaveTerm's layout/width engine thinks 👑 is 1 column wide, but its font renders the glyph across 2 columns
   anyway. (Incorrect)

Wave Version

v0.14.5

Platform

Windows

OS Version/Distribution

Win 11

Architecture

x64

Anything else?

I am ssh'd from Windows Powershell terminal widget into a VPS running Ubuntu. Then run tmux, then run pi coding agent within tmux.
But I think you can repo without pi