Make Shell a category, the bar legible, and the dock a real dock

Desktop & Dock becomes Shell — Bar, Dock, Control Center, Tiling,
Workspaces — the home for everything Quickshell draws. The settings-
management cluster moves to System as Sync & Backup, Appearance's
Shell tab dissolves, and 24-hour time finally lives on Date & Time,
which always owned it.

The bar gets what it never had: a way to survive the wallpaper. A
second neutral text family (follow theme, or forced light or dark),
a one-layer shadow under every glyph, and a gradient scrim for
wallpapers nothing else survives — all off by default, pixel-identical
until asked. Widgets earn toggles (weather, media, clipboard, calendar
countdown), the vitals cluster stops leaving a dead pill behind, and
Control Center's sections learn to step aside.

The dock graduates from MVP: a context menu with window rows, pin,
unpin, quit and new-window; scroll an icon to cycle its windows; drag
to reorder on the dock itself; hover previews with one-shot captures;
and "Add App to Dock" in the launcher. Three real bugs died en route —
menus that slid away with the autohide, a readonly-property crash on
every menu open, and a drag that drifted half a slot per icon on side
docks. The pinned-apps editor in Settings becomes a drag strip.

166 contracts; the full suite is green except two live display and
switcher tests that cannot run behind a locked session — re-verified
on unlock.

Claude-Session: https://claude.ai/code/session_01Ms2FbjQy31TVf3CEvQhGM8

config/dot/quickshell/services/SettingsRoutes.qml

@@ -33,7 +33,13 @@ Singleton {
             { page: "phone", label: "Phone" }
         ] },
         { page: "appearance", label: "Appearance", icon: "\u{F0E0D}", tabs: [] },
-        { page: "desktop", label: "Desktop & Dock", icon: "\u{F04A4}", tabs: [] },
+        { page: "shell", label: "Shell", icon: "\u{F04A4}", tabs: [
+            { page: "bar", label: "Bar" },
+            { page: "dock", label: "Dock" },
+            { page: "control-center", label: "Control Center" },
+            { page: "tiling", label: "Tiling" },
+            { page: "workspaces", label: "Workspaces" }
+        ] },
         { page: "displays", label: "Displays", icon: "\u{F0379}", tabs: [] },
         { page: "sound", label: "Sound", icon: "\u{F057E}", tabs: [] },
         { page: "notifications", label: "Notifications & Focus", icon: "\u{F009A}", tabs: [] },
@@ -72,7 +78,8 @@ Singleton {
             { page: "containers", label: "Containers" },
             { page: "datetime", label: "Date & Time" },
             { page: "region", label: "Region & Language" },
-            { page: "manual", label: "Manual" }
+            { page: "manual", label: "Manual" },
+            { page: "sync", label: "Sync & Backup" }
         ] }
     ]
 
@@ -104,7 +111,7 @@ Singleton {
     // Retired page ids keep resolving forever: old Vicinae commands, shell
     // history, and muscle memory all hold them. Each maps to the leaf that
     // absorbed its content.
-    readonly property var retired: ({ "home-phone": "my-home" })
+    readonly property var retired: ({ "home-phone": "my-home", "desktop": "bar" })
 
     // Any id a caller may hold — leaf, category, retired id, or garbage — to
     // the leaf that should render: a leaf resolves to itself, a category to