feat(menu): direct SUPER+CTRL+I / SUPER+CTRL+T binds for System and Tools

BACKLOG #107: both submenus get conflict-free direct bindings through
the canonical keybinds.nix (single source for Hyprland binds and the
SUPER+? cheatsheet) — I follows the Super+I settings muscle memory,
T is Tools. The root-menu rows now show the shortcuts via menuHint.

Verified: V2 — eval audit: 41 binds, no duplicate mods+key; both binds
present in the generated Hyprland config; built nomarchy-menu passes
bash -n with cheatsheet rows + hints rendered. In-session on the live
ISO KVM run: viewed 40-system-menu.png / 41-tools-menu.png in
/tmp/nomarchy-v2-swap-93/ — each bind opens its submenu directly.
V0 flake check green.

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

modules/home/keybinds.nix

@@ -54,6 +54,9 @@
     { mods = "$mod CTRL";   key = "P";      action = "exec, nomarchy-menu colorpicker"; desc = "Color picker (→ clipboard)"; }
     { mods = "$mod CTRL";   key = "A";      action = "exec, nomarchy-menu ask";       desc = "Ask Claude"; }
     { mods = "$mod CTRL";   key = "D";      action = "exec, nomarchy-menu dnd";       desc = "Do Not Disturb toggle"; }
+    # I as in "settings" muscle memory (Super+I elsewhere); T for Tools.
+    { mods = "$mod CTRL";   key = "I";      action = "exec, nomarchy-menu system";    desc = "System menu"; }
+    { mods = "$mod CTRL";   key = "T";      action = "exec, nomarchy-menu tools";     desc = "Tools menu"; }
     { mods = "$mod SHIFT";  key = "C";      action = "exec, hyprpicker -a";           desc = "Color picker (→ clipboard)"; }
 
     # Focus — SUPER + arrow keys.