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

types/donation.ts

@@ -34,6 +34,14 @@ export const DONATION_PRODUCTS = {
     amount: 25,
     price: 2500,
   },
+  custom: {
+    id: "custom",
+    name: "Valor Personalizado",
+    amount: 0,
+    price: 0,
+    minAmount: 1, // R$ 1,00
+    maxAmount: 10000, // R$ 10.000,00
+  },
 } as const;
 
 export type DonationTierId = keyof typeof DONATION_PRODUCTS;