feat: add Usage Limits Panel component with usage tracking and visual indicators for limits

style: implement custom color schemes and gradients for account section, enhancing visual hierarchy

frontend/src/pages/account/PlansAndBillingPage.tsx

@@ -502,6 +502,16 @@ export default function PlansAndBillingPage() {
                       buttonText: plan.id === currentPlanId ? 'Current Plan' : 'Select Plan',
                       highlighted: plan.is_featured || false,
                       disabled: plan.id === currentPlanId || planLoadingId === plan.id,
+                      // Plan limits
+                      max_sites: plan.max_sites,
+                      max_users: plan.max_users,
+                      max_keywords: plan.max_keywords,
+                      max_clusters: plan.max_clusters,
+                      max_content_ideas: plan.max_content_ideas,
+                      max_content_words: plan.max_content_words,
+                      max_images_basic: plan.max_images_basic,
+                      max_images_premium: plan.max_images_premium,
+                      included_credits: plan.included_credits,
                     };
                   })}
                   showToggle={true}