refactor: Align form validation UX across management dialogs

src/components/form/MultiSelectPopover.tsx

@@ -88,14 +88,14 @@ export function MultiSelectPopover({
   return (
     <Popover>
       <PopoverTrigger asChild>
-        <Button type="button" variant="outline" size="sm">
+        <Button type="button" variant="outline" size="sm" className="shadow-none">
           {icon}
           {label}
           <Badge variant="secondary">{values.length}</Badge>
           <ChevronDown />
         </Button>
       </PopoverTrigger>
-      <PopoverContent align={align} className="w-60 p-0">
+      <PopoverContent align={align} className="w-60 p-0 shadow-none">
         <div className="flex items-center gap-2 border-b p-3">
           <button
             type="button"