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).

shell/plugins/bar/widgets/systemStats.qml

@@ -2,6 +2,7 @@ import QtQuick
 import Quickshell
 import Quickshell.Io
 import qs.Ui
+import qs.Commons
 
 Item {
   id: root
@@ -188,7 +189,7 @@ Item {
         text: "System"
         color: root.bar.foreground
         font.family: root.bar.fontFamily
-        font.pixelSize: 12
+        font.pixelSize: Style.font.body
         font.bold: true
       }
 
@@ -217,13 +218,13 @@ Item {
           text: "Load"
           color: Qt.darker(root.bar.foreground, 1.5)
           font.family: root.bar.fontFamily
-          font.pixelSize: 11
+          font.pixelSize: Style.font.bodySmall
         }
         Text {
           text: root.loadAvg.toFixed(2)
           color: root.bar.foreground
           font.family: root.bar.fontFamily
-          font.pixelSize: 11
+          font.pixelSize: Style.font.bodySmall
         }
       }
     }
@@ -246,14 +247,14 @@ Item {
         text: detail.title
         color: Qt.darker(detail.barFg, 1.4)
         font.family: detail.fontFamily
-        font.pixelSize: 11
+        font.pixelSize: Style.font.bodySmall
       }
       Item { width: detail.width - parent.children[0].implicitWidth - parent.children[2].implicitWidth; height: 1 }
       Text {
         text: detail.value
         color: detail.barFg
         font.family: detail.fontFamily
-        font.pixelSize: 11
+        font.pixelSize: Style.font.bodySmall
       }
     }