refine: Clean up action button design and fix padding issues

- Remove small circle indicator from Action icon for cleaner plus symbol
- Fix button padding conflicts by using !px-0 to override default padding:
  - Action button: Remove left/right padding for tighter spacing
  - Attach button: Remove left/right padding for tighter spacing
- Ensure buttons render without horizontal padding as intended

UI improvements:
- Cleaner, more minimal plus icon design
- Consistent compact button spacing
- Better visual alignment in bottom bar

ui/desktop/src/components/ChatInput.tsx

@@ -1676,7 +1676,7 @@ export default function ChatInput({
               onClick={handleActionButtonClick}
               variant="ghost"
               size="sm"
-              className="flex items-center text-text-default/70 hover:text-text-default text-xs cursor-pointer transition-colors px-0"
+              className="flex items-center text-text-default/70 hover:text-text-default text-xs cursor-pointer transition-colors !px-0"
             >
               <Action className="w-4 h-4 min-[1050px]:mr-1" />
               <span className="text-xs hidden min-[1050px]:inline">Actions</span>
@@ -1694,7 +1694,7 @@ export default function ChatInput({
               onClick={handleFileSelect}
               variant="ghost"
               size="sm"
-              className="flex items-center text-text-default/70 hover:text-text-default text-xs cursor-pointer transition-colors px-0"
+              className="flex items-center text-text-default/70 hover:text-text-default text-xs cursor-pointer transition-colors !px-0"
             >
               <Attach className="w-4 h-4 min-[1050px]:mr-1" />
               <span className="text-xs hidden min-[1050px]:inline">Attach</span>

ui/desktop/src/components/icons/Action.tsx

@@ -21,8 +21,6 @@ const Action: React.FC<ActionProps> = ({ className = '', size = 16 }) => {
       {/* Plus symbol */}
       <line x1="12" y1="5" x2="12" y2="19"></line>
       <line x1="5" y1="12" x2="19" y2="12"></line>
-      {/* Action indicator - small circle at bottom right */}
-      <circle cx="18" cy="18" r="3" fill="currentColor" stroke="none" opacity="0.8"></circle>
     </svg>
   );
 };