feat: Enhance ScreenDesigner with alignment and distribution features

- Added new alignment, distribution, and size matching functionalities to the ScreenDesigner component.
- Implemented keyboard shortcuts for nudging components and toggling labels.
- Introduced a modal for displaying keyboard shortcuts to improve user experience.
- Updated SlimToolbar to support new alignment and distribution actions based on selected components.
- Enhanced zoom control with RAF throttling to prevent flickering during zoom operations.

frontend/components/v2/V2Select.tsx

@@ -122,7 +122,13 @@ const DropdownSelect = forwardRef<HTMLButtonElement, {
           role="combobox"
           aria-expanded={open}
           disabled={disabled}
-          className={cn("w-full justify-between font-normal", className)}
+          className={cn(
+            "w-full justify-between font-normal",
+            "bg-transparent hover:bg-transparent", // 표준 Select와 동일한 투명 배경
+            "border-input shadow-xs", // 표준 Select와 동일한 테두리
+            "h-6 px-2 py-0 text-sm", // 표준 Select xs와 동일한 높이
+            className,
+          )}
           style={style}
         >
           <span className="truncate flex-1 text-left">