Unify font sizes through qs.Commons.Style

Themes now drive typography the same way they drive colors: one [font]
base-size in shell.toml is the rem root, and every Style.font.<token>
(caption, bodySmall, body, subtitle, title, heading, display,
displayLarge, iconSmall, icon, iconLarge) derives from it via a fixed
multiplier. Themes can also pin individual tokens for stylistic
emphasis. base-size is clamped 11..13 until row-height tokens exist.

Bar dimensions move to the same singleton: [bar] size-horizontal /
size-vertical replace the hardcoded 26/28 in Bar.qml, exposed as
Style.bar.sizeHorizontal / sizeVertical.

Style.qml also resolves the fontconfig 'monospace' alias via fc-match
and exposes Style.font.resolvedFamily so panels can display the
concrete family. Watches ~/.config/fontconfig/fonts.conf so it tracks
'omarchy font set <name>'.

The qs.Ui kit (PillButton, Dropdown, Toggle, TextField, etc.) and
every first-party plugin (bar widgets, settings, menu, clipboard,
emoji, polkit, notifications, osd, image-picker, dev-gallery) now
bind to Style.font.* instead of pixel literals. Only three deliberate
display-scale outliers remain: the notification empty-state glyph and
the weather flyout's hero temperature pair, all commented.

Background plugin's applyTheme IPC fast-path also pushes shell.toml to
Style so theme swaps update typography and bar size without waiting
for inotify debounce.

Dev gallery (omarchy dev ui-preview) now ships a Typography section
that renders the full scale and theme tokens live, and its summon
command is fixed (omarchy-shell-ipc -> omarchy-shell).

default/themed/shell.toml.tpl

@@ -1,11 +1,37 @@
-# Omarchy shell colors. Defaults derive from colors.toml; themes can ship
-# themes/<name>/shell.toml to override individual keys.
+# Omarchy shell surfaces. Colors derive from colors.toml; sizes and the
+# typographic scale come from the keys below. Themes can ship
+# themes/<name>/shell.toml to override any individual key.
 
 [bar]
 background = "{{ background }}"
 text       = "{{ foreground }}"
 # Modules calling attention to themselves (recording, voxtype, alerts, updates)
 active     = "{{ color1 }}"
+# Cross-axis size in px. size-horizontal is the height of top/bottom bars;
+# size-vertical is the width of left/right bars.
+size-horizontal = 26
+size-vertical   = 28
+
+[font]
+# base-size is the rem root for the type scale. Every Style.font.<token>
+# derives from it (e.g. body = base, subtitle ≈ base * 1.083,
+# heading ≈ base * 1.333). Clamped 11..13 by the shell — row heights are
+# fixed until we ship matching spacing tokens, so growth would clip.
+base-size = 12
+# Per-token overrides, in px. Uncomment any to pin a specific size without
+# affecting the rest of the scale. Useful for stylistic emphasis (a
+# minimalist theme that wants a bigger heading without scaling everything).
+# caption       = 10
+# body-small    = 11
+# body          = 12
+# subtitle      = 13
+# title         = 14
+# heading       = 16
+# display       = 24
+# display-large = 28
+# icon-small    = 11
+# icon          = 14
+# icon-large    = 18
 
 [popups]
 # Shared by every bar flyout. Body text inside flyouts is not separately