### System details

AMD Ryzen 7 9800X3D, AMD Radeon RX 9070-series, Omarchy 4.0.0-1

### What's wrong?

Omarchy's font picker recognizes only fonts classified by Fontconfig as `FC_MONO` (`spacing=100`). It excludes fonts classified as `FC_DUAL` (`spacing=90`), even though that is also a fixed-grid spacing category: glyphs have precisely two advance widths, one exactly twice the other. Such fonts can represent one-cell and two-cell glyphs and remain compatible with terminal grids.

[Mona Sans Mono](https://github.com/github/mona-sans#mona-sans-mono-styles) is one reproducible example. It is installed, matched by Fontconfig, and can be applied with `omarchy font set`, but it is absent from `omarchy font list` and the Style > Font picker:

```console
$ fc-match "Mona Sans Mono"
MonaSansMono-Regular.ttf: "Mona Sans Mono" "Regular"

$ fc-query -f 'family=%{family[0]} spacing=%{spacing}\n' \
    ~/.local/share/fonts/Mona\ Sans\ Mono/MonaSansMono-Regular.ttf
family=Mona Sans Mono spacing=90

$ omarchy font list | grep -F "Mona Sans Mono"
# no output

$ omarchy font set "Mona Sans Mono"
# succeeds
```

The exclusion comes from the strict filter in `omarchy-font-list`:

```bash
fc-list :spacing=100 -f "%{family[0]}\n" | grep -v -i -E 'emoji|signwriting|omarchy' | sort -u
```

Fontconfig documents `FC_DUAL` as distinct from proportional spacing: [Fontconfig developer documentation](https://fontconfig.pages.freedesktop.org/fontconfig/fontconfig-devel/).

Is strict `FC_MONO` an intentional compatibility requirement for an Omarchy component? If not, the font picker should also discover compatible `FC_DUAL` fonts. If dual-width fonts are intentionally unsupported, it may be better for `omarchy font set` to validate that consistently or for the limitation to be documented.