Lower hover dock position by 24px

- Change marginBottom from '8px' to '-16px' to position dock closer to input
- This moves the dock approximately 24px lower as requested
- Maintains proper hover interaction while bringing dock closer to chat input

ui/desktop/src/components/Layout/SidecarInvoker.tsx

@@ -196,7 +196,7 @@ export const SidecarInvoker: React.FC<SidecarInvokerProps> = ({
           ? 'opacity-100 translate-y-0' 
           : 'opacity-0 -translate-y-2 pointer-events-none'
       }`}
-      style={{ marginBottom: '8px' }} // Add spacing above the floating input
+      style={{ marginBottom: '-16px' }} // Position dock closer to the floating input
     >
       {/* Screenshot backdrops - positioned behind the dock */}
       {iframeBackdrops.map((backdrop) => (