fix(keybinds): SUPER+? bind uses base keysym slash, not question

Item 32. Item 26 added SHIFT to the modmask but kept the shifted keysym
`question`, so the bind stayed dead. Hyprland 0.55 resolves a bind's
keysym with SHIFT consumed (issue #7750, behaviour since 0.43): with
Shift held, `$mod SHIFT, question` is matched against `slash` and never
fires. The base keysym is what works — same pattern as this file's own
`$mod SHIFT, 1` workspace binds. Also updates rofi.nix prettyKeys to
collapse "SHIFT + /" → "?" so the cheatsheet row still reads "SUPER + ?".

Verified: V0 `nix flake check --no-build` green; V1 HM activation built,
built hyprland.conf carries `bind=$mod SHIFT, slash, exec, nomarchy-menu
keybinds` (kb_layout=us → slash is `?`). The keypress opening the menu is
V3 — queued (HARDWARE-QUEUE, existing SUPER+? entry updated).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent/BACKLOG.md

@@ -26,14 +26,6 @@ next, in what order*.
 
 ## NEXT
 
-### 32. SUPER+? cheatsheet bind still not opening `[bug]`
-(Raised by Bernardo, 2026-07-07 — item 2.) Item 26's fix (SHIFT in the
-bind modmask so the shifted `question` keysym fires) shipped, but SUPER+?
-still doesn't open the keybindings cheatsheet. Re-diagnose: confirm the
-Hyprland bind's modmask/keysym against the *actual* layout, whether rofi
-2.0.0 changed anything, and that the cheatsheet path still resolves.
-
-
 ### 36. Battery / power quick menu `[human]`
 (Raised by Bernardo, 2026-07-07 — item 6.) Slice (a) — the charge-threshold
 toggle in the rofi System submenu — shipped 2026-07-07 (iteration #64;