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/menu/Menu.qml

@@ -871,7 +871,7 @@ Item {
             color: root.foreground
             opacity: root.filterText ? 1 : 0.58
             font.family: root.fontFamily
-            font.pixelSize: 16
+            font.pixelSize: Style.font.heading
             elide: Text.ElideRight
           }
 
@@ -946,7 +946,7 @@ Item {
                 color: index === root.selectedIndex ? root.accent : root.foreground
                 opacity: row.kind === "back" ? 0.7 : 1
                 font.family: root.fontFamily
-                font.pixelSize: 18
+                font.pixelSize: Style.font.iconLarge
                 width: 36
                 horizontalAlignment: Text.AlignHCenter
                 verticalAlignment: Text.AlignVCenter
@@ -970,7 +970,7 @@ Item {
                   text: row.label
                   color: index === root.selectedIndex ? root.accent : root.foreground
                   font.family: root.fontFamily
-                  font.pixelSize: 16
+                  font.pixelSize: Style.font.heading
                   font.weight: Font.Medium
                   elide: Text.ElideRight
                 }
@@ -982,7 +982,7 @@ Item {
                   color: root.foreground
                   opacity: 0.52
                   font.family: root.fontFamily
-                  font.pixelSize: 11
+                  font.pixelSize: Style.font.bodySmall
                   elide: Text.ElideRight
                 }
               }
@@ -1001,7 +1001,7 @@ Item {
                   color: root.foreground
                   opacity: 0.45
                   font.family: root.fontFamily
-                  font.pixelSize: 12
+                  font.pixelSize: Style.font.body
                   anchors.verticalCenter: parent.verticalCenter
                 }
 
@@ -1010,7 +1010,7 @@ Item {
                   color: index === root.selectedIndex ? root.accent : root.foreground
                   opacity: row.kind === "menu" || row.kind === "link" ? 0.36 : 0
                   font.family: root.fontFamily
-                  font.pixelSize: 16
+                  font.pixelSize: Style.font.heading
                   font.weight: Font.Normal
                   anchors.verticalCenter: parent.verticalCenter
                 }
@@ -1036,7 +1036,7 @@ Item {
               color: root.accent
               opacity: 0.8
               font.family: root.fontFamily
-              font.pixelSize: 28
+              font.pixelSize: Style.font.displayLarge
               horizontalAlignment: Text.AlignHCenter
               width: 320
             }
@@ -1046,7 +1046,7 @@ Item {
               color: root.foreground
               opacity: 0.7
               font.family: root.fontFamily
-              font.pixelSize: 14
+              font.pixelSize: Style.font.title
               horizontalAlignment: Text.AlignHCenter
               width: 320
             }