Improve admin UI and vendor invite experience

Enhanced the admin dashboard tab styling for better clarity. Refactored InviteVendorCard with improved UI, feedback, and clipboard copy functionality. Fixed vendor store ID update to send raw object instead of JSON string. Ensured product price formatting is robust against non-numeric values.

components/dashboard/content.tsx

@@ -181,7 +181,7 @@ export default function Content({ username, orderStats }: ContentProps) {
                       <div className="flex-grow min-w-0">
                         <h4 className="font-semibold text-lg truncate group-hover:text-primary transition-colors">{product.name}</h4>
                         <div className="flex items-center gap-3 mt-0.5">
-                          <span className="text-sm text-muted-foreground font-medium">£{product.price.toFixed(2)}</span>
+                          <span className="text-sm text-muted-foreground font-medium">£{(Number(product.price) || 0).toFixed(2)}</span>
                           <span className="h-1 w-1 rounded-full bg-muted-foreground/30" />
                           <span className="text-xs text-muted-foreground">ID: {product.id.slice(-6)}</span>
                         </div>