feat(waybar): highlight active workspace and flag urgent ones

Style the `hyprland/workspaces` buttons so the focused workspace is
distinguishable when several are occupied: white text, darker
background, blue underline; urgent workspaces turn red.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

modules/home.nix

@@ -687,6 +687,18 @@ in
       #battery.charging {
         color: #98c379;
       }
+      #workspaces button {
+        padding: 0 8px;
+        color: #bbbbbb;
+      }
+      #workspaces button.active {
+        color: #ffffff;
+        background: #333333;
+        box-shadow: inset 0 -2px #61afef;
+      }
+      #workspaces button.urgent {
+        color: #e06c75;
+      }
     '';
   };
 }