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/options.nix

@@ -56,6 +56,31 @@ in
         explicit value into the generated home.nix.
       '';
     };
+    keymap = {
+      layout = lib.mkOption {
+        type = lib.types.str;
+        default = "us";
+        example = "dk";
+        description = ''
+          Keyboard layout for Hyprland's native Wayland session. The
+          installer also writes services.xserver.xkb.layout (for XWayland)
+          and console.keyMap (for the TTY) to the same value via
+          system.nix, but Hyprland reads its own input config so it needs
+          this option independently — otherwise non-US users get the
+          right layout in XWayland apps and the console but the US
+          fallback inside native-Wayland apps.
+        '';
+      };
+      variant = lib.mkOption {
+        type = lib.types.str;
+        default = "";
+        example = "intl";
+        description = ''
+          Keyboard variant for Hyprland (e.g. "intl" for US-International).
+          Empty by default.
+        '';
+      };
+    };
     wallpaper = lib.mkOption {
       type = lib.types.str;
       default = schema.home.wallpaper;