feat(x1g9): remap VXE mouse buttons

hosts/default.nix

@@ -91,6 +91,9 @@
       "workload.game"
       "workload.personal"
     ];
+
+    # The VXE wireless mouse dongle is used only with this host.
+    units = [ "services.evremap" ];
   };
 
   galleria = {

modules/services/evremap/nixos.nix

@@ -0,0 +1,20 @@
+{
+  services.evremap = {
+    enable = true;
+
+    settings = {
+      device_name = "VXE VXE Mouse 1K Dongle Mouse";
+
+      remap = [
+        {
+          input = [ "BTN_SIDE" ];
+          output = [ "KEY_LEFTMETA" ];
+        }
+        {
+          input = [ "BTN_EXTRA" ];
+          output = [ "BTN_SIDE" ];
+        }
+      ];
+    };
+  };
+}