feat(donations): add custom donation tier with flexible amount selection

- Updated support page grid layout to accommodate new custom donation card
- Enhanced API route to validate and process custom donation amounts (min/max limits)
- Modified donation card component to include custom amount input field
- Ensures users can donate any amount within specified range, improving donation flexibility

app/[locale]/apoiar/page.tsx

@@ -170,7 +170,7 @@ export default async function SupportPage({
             <h2 className="text-3xl font-bold text-center mb-8">
               Escolha como apoiar
             </h2>
-            <div className="grid grid-cols-1 md:grid-cols-3 gap-8 max-w-4xl mx-auto">
+            <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-4 gap-8 max-w-6xl mx-auto">
               <DonationCard
                 id="coffee"
                 amount={5}
@@ -196,6 +196,12 @@ export default async function SupportPage({
                 icon="pizza"
                 badge={t("tiers.lunch.badge")}
               />
+              <DonationCard
+                id="custom"
+                title="Personalizado"
+                description="Escolha quanto quer doar"
+                icon="heart"
+              />
             </div>
           </div>
         </BlurFade>