feat(accessibility): home-side Hyprland companion

New nomarchy.accessibility.enable home option mirroring
nomarchy.system.accessibility.enable. When enabled, core/home/
accessibility.nix contributes a Hyprland extraConfig block via
lib.mkAfter:

  - input.repeat_rate = 25 (from 40)
  - input.repeat_delay = 1000 ms (from 600)
    Holding a key isn't a runaway machine-gun for low-mobility users.

  - bindd = SUPER ALT, S, Launch Orca, exec, orca
    The system preset already puts orca on PATH.

mkAfter guarantees the slowdown wins over the templated input.conf.
Documented in docs/OPTIONS.md. The third item from the original Next
row — a high-contrast palette — is split into its own Later row
because it's a design task (24-colour WCAG AAA palette + icon family
choice) that wants its own review.

`nix flake check --no-build` clean.

core/home/accessibility.nix

@@ -0,0 +1,28 @@
+{ config, lib, ... }:
+
+let
+  cfg = config.nomarchy.accessibility;
+in
+{
+  config = lib.mkIf cfg.enable {
+    # Hyprland-side accessibility extras. The system preset
+    # (core/system/accessibility.nix) covers AT-SPI2 + Orca on PATH +
+    # XCURSOR_SIZE; this module adds the bits Hyprland reads directly.
+    #
+    # Loaded via extraConfig (mkAfter) so it merges with — and overrides
+    # — the templated input.conf for the repeat-rate / repeat-delay
+    # fields. The Orca keybinding is additive.
+    wayland.windowManager.hyprland.extraConfig = lib.mkAfter ''
+      # Accessibility — slower key-repeat so holding a key isn't a
+      # runaway machine-gun for users with low-mobility hands.
+      input {
+        repeat_rate = 25
+        repeat_delay = 1000
+      }
+
+      # Launch the Orca screen reader. The system preset puts `orca`
+      # on PATH when nomarchy.system.accessibility.enable = true.
+      bindd = SUPER ALT, S, Launch Orca, exec, orca
+    '';
+  };
+}