feat(keymap): route installer layout choice into Hyprland's Wayland session

core/home/config/nomarchy/default/hypr/input.conf hardcoded
`kb_layout = us`, so the installer's services.xserver.xkb.layout and
console.keyMap writes (both set from the installer's KEYMAP_LAYOUT
prompt) only reached XWayland apps and the TTY console. Native-Wayland
apps — i.e. almost everything in a Nomarchy desktop — fell back to US
regardless of what the user picked. Surprising for any non-US user.

Path (a) from the Later row:

  - Added nomarchy.keymap.{layout,variant} to core/home/options.nix
    (defaults "us" / "").
  - Deleted the static input.conf from the bulk nomarchy/ deploy.
  - Replaced it with an explicit
    xdg.configFile."nomarchy/default/hypr/input.conf".text in
    core/home/configs.nix that interpolates the option values into
    kb_layout / kb_variant.
  - Installer's home.nix heredoc now writes
      nomarchy.keymap = { layout = "$KEYMAP_LAYOUT"; variant = "$KEYMAP_VARIANT"; };
    alongside nomarchy.formFactor, so the layout reaches Hyprland
    consistently with system.nix's xkb.layout / console.keyMap.

Documented in docs/OPTIONS.md (new `nomarchy.keymap.layout` /
`nomarchy.keymap.variant` entry). `nix flake check --no-build` clean.

core/home/config/nomarchy/default/hypr/input.conf

@@ -1,21 +0,0 @@
-# https://wiki.hyprland.org/Configuring/Variables/#input
-input {
-    kb_layout = us
-    kb_variant =
-    kb_model =
-    kb_options = compose:caps
-    kb_rules =
-
-    follow_mouse = 1
-
-    sensitivity = 0 # -1.0 - 1.0, 0 means no modification.
-
-    touchpad {
-        natural_scroll = false
-    }
-}
-
-misc {
-    key_press_enables_dpms = true  # key press will trigger wake
-    mouse_move_enables_dpms = true # mouse move will trigger wake
-}