feat(a11y): apply ARIA roles, landmarks, focus management, touch targets and contrast fixes across components

dashboard/src/components/ui/dialog.tsx

@@ -54,7 +54,7 @@ const DialogContent = React.forwardRef<
       {!hideCloseButton && (
         <DialogPrimitive.Close className="absolute right-4 top-4 rounded-sm opacity-70 ring-offset-background transition-opacity hover:opacity-100 focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2 disabled:pointer-events-none data-[state=open]:bg-accent data-[state=open]:text-muted-foreground">
           <X className="h-4 w-4" />
-          <span className="sr-only">Close</span>
+          <span className="sr-only">关闭</span>
         </DialogPrimitive.Close>
       )}
     </DialogPrimitive.Content>