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/manual/04-when-something-breaks.md

@@ -3,7 +3,7 @@
 ## Start here
 
 Run **Check System Health** from the launcher, or open Settings and go to
-System Health. It reports what is actually running rather than what was
+System, then the System Health tab. It reports what is actually running rather than what was
 installed, and it can repair several things itself.
 
 From a terminal, the same check is `panama doctor`.
@@ -20,8 +20,8 @@ From a terminal: `qs -d` starts the shell again.
 ## A shortcut stopped working
 
 Check `Super + /` first: if the shortcut shows a different chord than you
-expect, something rebound it. The Shortcuts settings page can reset any bind,
-or all of them at once.
+expect, something rebound it. The Keyboard page, under Input in Settings, can
+reset any bind, or all of them at once.
 
 If the whole keymap is missing from that list, the compositor config failed
 to load. `Hyprland --verify-config` says why without touching your session.
@@ -47,8 +47,9 @@ harmed by being refused.
 `panama migrate` applies repairs this machine has not had yet. It is safe to
 run at any time and does nothing when there is nothing to do.
 
-If an update went badly, the Snapshots settings page can roll the system back
-where btrfs snapshots are configured.
+If an update went badly, the Snapshots tab under System in Settings can roll
+the system back. That tab is only there where btrfs snapshots are configured,
+so if you cannot see it, this machine has none to roll back to.
 
 ## Reporting it