feat(menu): Look & Feel category — theme, wallpaper, night light (item 19)

The gate was >=3 appearance entries and it's met: the root's Theme row
becomes "Look & Feel" (pango-escaped & — the root passes
-markup-rows; matched on *Look*), a new lookfeel submenu carries the
Theme grid (SUPER+T hint), Next wallpaper (SUPER+SHIFT+T hint via the
new generalized hintForAction, which menuHint is now sugar over), and
the Night light toggle moved out of System — which thins by one row.
The root stays at six entries; both direct binds still hit the leaves.

Verified: V0; V1 — rendered menu passes bash -n with the mode, escaped
label and relocated night-light row; visual — tokyo-night 1080p
capture renders "Look & Feel" correctly with hints intact. Submenu
flow queued for a session test (HARDWARE-QUEUE).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

agent/HARDWARE-QUEUE.md

@@ -167,6 +167,10 @@ QA machine), the **T14s** (webcam case).
       (tooltips, fastfetch labels) is visible on summer-day +
       flexoki-light, kanagawa floats are lighter than the bg (upstream
       sumiInk4). Anything that reads worse than before → reopen 28b.
+- [ ] **Look & Feel submenu (item 19)** — root menu: "Look & Feel"
+      (replacing Theme, root still six rows) → Theme grid opens, Next
+      wallpaper cycles instantly, Night light toggles (and is GONE
+      from System). SUPER+T / SUPER+SHIFT+T direct binds unchanged.
 - [ ] **Launch-or-focus (item 17)** — uncomment the template's
       `nomarchy.launchOrFocus` firefox example (with firefox
       installed), `home-update` + reload: SUPER+B launches firefox