refactor(ui): unify dialog styles and improve layout consistency

Standardize dialog and panel components across the application.
- Update dialog background to use semantic color tokens
- Adjust FullScreenPanel max-width to 56rem for better alignment
- Add drag region and prevent body scroll in full-screen panels
- Optimize button sizes and spacing in panel headers
- Apply consistent styling to all dialog-based components

src/components/ui/dialog.tsx

@@ -65,7 +65,7 @@ const DialogContent = React.forwardRef<
 
     const variantClass = {
       default:
-        "fixed left-1/2 top-1/2 flex flex-col w-full max-w-lg max-h-[90vh] translate-x-[-50%] translate-y-[-50%] border border-border-default bg-white dark:bg-gray-900 shadow-lg duration-200 data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[state=closed]:slide-out-to-left-1/2 data-[state=closed]:slide-out-to-top-[48%] data-[state=open]:slide-in-from-left-1/2 data-[state=open]:slide-in-from-top-[48%] sm:rounded-lg",
+        "fixed left-1/2 top-1/2 flex flex-col w-full max-w-lg max-h-[90vh] translate-x-[-50%] translate-y-[-50%] border border-border-default bg-background text-foreground shadow-lg duration-200 data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[state=closed]:slide-out-to-left-1/2 data-[state=closed]:slide-out-to-top-[48%] data-[state=open]:slide-in-from-left-1/2 data-[state=open]:slide-in-from-top-[48%] sm:rounded-lg",
       fullscreen:
         "fixed inset-0 flex flex-col w-screen h-screen translate-x-0 translate-y-0 bg-background text-foreground p-0 sm:rounded-none shadow-none",
     }[variant];