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/hypr/README.md

@@ -119,7 +119,7 @@ shipped one, so a hand-edited `settings.json` cannot cost you a keymap.
 Every `hl.bind` must pass a `description`. Hyprland reports Lua-defined binds
 with dispatcher `__lua` and a bytecode offset as the argument, so a bind without
 one has nothing readable beside its chord, and the Settings app drops it from the
-Input & Shortcuts page rather than showing a mystery row.
+Keyboard page under Input rather than showing a mystery row.
 `tests/quickshell/keybinds-contract` fails if any bind lacks a description, so
 this cannot regress silently.