nerd fonts fail to display glyphs

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**Describe the bug**
When using a Nerd Font with Glyphs, the Glyphs are shown as something like a broken Unicode empty box instead of the real glyph.

**Setup**
- OS: MACOS
- Shell: ZSH
- Terminal Emulator: GHOSTTY
- Terminal Multiplexer: TMUX

**To Reproduce**
Steps to reproduce the behavior:
1. vhs eza.demo.tape (see tape below)
2. open eza.demo.gif
3. See error

**Source Code**
```
# eza.demo.tape
Output eza.demo.gif
Require eza
Set Shell "bash"
Set FontFamily "0xProto Nerd Font Mono"
Set FontSize 24
Set Width 1200
Set Height 600
Type "vhs --version" Sleep 300ms Enter
Sleep 200ms Enter Sleep 50ms Enter Enter
Type "eza --icons=always --tree /opt/homebrew/Cellar/vhs" Sleep 500ms Enter
Sleep 500ms
Enter
Sleep 5s
```

**Expected behavior**
Nerd Font glyphs are displayed in full glory

**Screenshots**
Expected output:

Actual output:

**Additional context**
Here's my full GhosTTY config:
```
background-blur = "true"
background-opacity = "0.75"
font-family = "0xProto Nerd Font Mono"
font-size = "13"
macos-titlebar-style = "hidden"
shell-integration = "none"
theme = "dark:catppuccin-mocha,light:catppuccin-latte"
window-inherit-working-directory = "false"
window-save-state = "never"
working-directory = "home"
```

Start by running the issue's eza.demo.tape with the specified Nerd Font setup and inspect the generated eza.demo.gif against the expected screenshot. Trace the VHS rendering path involved in font glyph output; done means the reproduction displays Nerd Font icons rather than broken Unicode boxes.

Written by the indexing model from the issue text.