refactor(hyprland): move terminal keybind into registry

configs/nixos/registry/keybind.nix

@@ -0,0 +1,37 @@
+{ lib, util, ... }:
+{
+  checks = [
+    {
+      assertion = util.registry.predicates.uniquePerHost (entry: entry.value.keys);
+      message = "Desktop keybinds must use unique key chords per host.";
+    }
+  ];
+
+  type = lib.types.submodule {
+    options = {
+      keys = lib.mkOption {
+        description = "Sets the key chord for this desktop keybind.";
+        type = lib.types.str;
+        example = "SUPER + Return";
+      };
+
+      action = lib.mkOption {
+        description = "Declares the action this keybind runs.";
+        type = lib.types.submodule {
+          options = {
+            kind = lib.mkOption {
+              description = "Selects the keybind action kind.";
+              type = lib.types.enum [ "exec" ];
+            };
+
+            command = lib.mkOption {
+              description = "Command executed by this keybind.";
+              type = lib.types.str;
+              example = "ghostty";
+            };
+          };
+        };
+      };
+    };
+  };
+}