fix: consolidate duplicate scrollbar hiding classes

- Remove duplicate .hide-scrollbar class (lines 483-489)
- Update ChatTextArea.tsx to use consolidated .scrollbar-hide class
- Both classes were functionally identical, keeping the first one with proper documentation

Author: MuriloFP

webview-ui/src/components/chat/ChatTextArea.tsx

@@ -947,7 +947,7 @@ const ChatTextArea = forwardRef<HTMLTextAreaElement, ChatTextAreaProps>(
 									"flex-none flex-grow",
 									"z-[2]",
 									"scrollbar-none",
-									"hide-scrollbar",
+									"scrollbar-hide",
 								)}
 								onScroll={() => updateHighlights()}
 							/>

webview-ui/src/index.css

@@ -479,11 +479,3 @@ input[cmdk-input]:focus {
 	transition-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
 	transition-duration: 150ms;
 }
-
-.hide-scrollbar {
-	scrollbar-width: none; /* Firefox */
-	-ms-overflow-style: none; /* IE 10+ */
-}
-.hide-scrollbar::-webkit-scrollbar {
-	display: none; /* Chrome/Safari/Webkit */
-}