Fold thirty-one settings pages into fifteen categories with tabs

The sidebar was a flat scan of thirty-one rows; now it reads like a
settings app. Multi-subject categories (Input, Network & Sharing,
Applications, Users & Accounts, Privacy & Security, System) carry an
Appearance-style tab strip above the page, drawn by the shell so the
leaf pages themselves are untouched. The taxonomy lives in one new
file, services/SettingsRoutes.qml; the sidebar, the strip, route
validation, search breadcrumbs, and both generators derive from it.

ShellState.settingsPage still holds leaf ids, so every deep link, IPC
call, and search result keeps working — and now lands on the exact
tab. Dictation moves out of Sound onto its own page under Input, with
a handoff back to Sound for the microphone. The strip scrolls when
System's nine tabs outgrow a tiled window. All 161 contracts pass.

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

config/dot/quickshell/modules/settings/ConnectivityPage.qml

@@ -1,4 +1,4 @@
-// Network & Devices.
+// Connections — wired, Wi-Fi, and Bluetooth.
 //
 // Wi-Fi and Bluetooth are handled here rather than delegated. Everything goes
 // through Quickshell.Networking and Quickshell.Bluetooth -- NetworkManager and
@@ -20,7 +20,7 @@ SettingsPage {
     id: root
 
 
-    title: "Network & Devices"
+    title: "Connections"
     lede: Connectivity.activeNetwork
         ? "Connected to " + Connectivity.activeNetwork.name
         : "Wi-Fi, Bluetooth, and the things Fedora owns."