feat: enhance column width configuration and rendering

- Updated the column width handling in various components to support percentage-based widths, improving layout flexibility.
- Adjusted input fields to enforce minimum and maximum width constraints, ensuring better user experience and preventing layout issues.
- Enhanced the SortableColumnRow and related components to dynamically display width units, allowing for clearer configuration options.

Made-with: Cursor

frontend/components/v2/config-panels/V2SplitPanelLayoutConfigPanel.tsx

@@ -157,10 +157,13 @@ function SortableColumnRow({
       />
       <Input
         value={col.width || ""}
-        onChange={(e) => onWidthChange(parseInt(e.target.value) || 100)}
-        placeholder="너비"
+        onChange={(e) => onWidthChange(parseInt(e.target.value) || 20)}
+        placeholder="20"
         className="h-6 w-14 shrink-0 text-xs"
+        min={5}
+        max={100}
       />
+      <span className="text-muted-foreground shrink-0 text-[10px]">%</span>
       {isNumeric && (
         <label
           className="flex shrink-0 cursor-pointer items-center gap-1 text-[10px]"