feat: add donation support with footer card and navigation

Add donation functionality to encourage community support, including a footer card on the home page, a highlighted "Apoiar" link in the header, and comprehensive English messages for the donation section to promote transparency and user engagement.

lib/abacatepay.ts

@@ -0,0 +1,100 @@
+interface AbacatePayConfig {
+  apiKey: string;
+  accountId: string;
+  baseUrl?: string;
+}
+
+interface CreateBillingParams {
+  amount: number;
+  metadata?: {
+    donorName?: string;
+    donorEmail?: string;
+    message?: string;
+  };
+  returnUrl?: string;
+  completionUrl?: string;
+}
+
+interface BillingResponse {
+  id: string;
+  amount: number;
+  status: "PENDING" | "PAID" | "EXPIRED" | "CANCELLED";
+  pixCode: string;
+  pixQrCode: string;
+  expiresAt: string;
+  createdAt: string;
+}
+
+class AbacatePayClient {
+  private config: AbacatePayConfig;
+
+  constructor(config: AbacatePayConfig) {
+    this.config = {
+      ...config,
+      baseUrl: config.baseUrl || "https://api.abacatepay.com/v1",
+    };
+  }
+
+  async createBilling(params: CreateBillingParams): Promise<BillingResponse> {
+    const response = await fetch(`${this.config.baseUrl}/billing`, {
+      method: "POST",
+      headers: {
+        Authorization: `Bearer ${this.config.apiKey}`,
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({
+        account_id: this.config.accountId,
+        amount: params.amount * 100, // centavos
+        metadata: params.metadata,
+        return_url: params.returnUrl,
+        completion_url: params.completionUrl,
+      }),
+    });
+
+    if (!response.ok) {
+      const errorData = await response.json().catch(() => ({}));
+      throw new Error(
+        `Failed to create billing: ${errorData.message || response.statusText}`
+      );
+    }
+
+    return response.json();
+  }
+
+  async getBillingStatus(billingId: string): Promise<BillingResponse> {
+    const response = await fetch(
+      `${this.config.baseUrl}/billing/${billingId}`,
+      {
+        headers: {
+          Authorization: `Bearer ${this.config.apiKey}`,
+        },
+      }
+    );
+
+    if (!response.ok) {
+      const errorData = await response.json().catch(() => ({}));
+      throw new Error(
+        `Failed to get billing status: ${
+          errorData.message || response.statusText
+        }`
+      );
+    }
+
+    return response.json();
+  }
+
+  verifyWebhookSignature(payload: string, signature: string): boolean {
+    // Implementar verificação de assinatura conforme documentação do AbacatePay
+    // Por enquanto, retorna true para desenvolvimento
+    // Em produção, implementar a verificação real
+    return true;
+  }
+}
+
+// Instância do cliente (será configurada com variáveis de ambiente)
+export const abacatePay = new AbacatePayClient({
+  apiKey: process.env.ABACATEPAY_API_KEY || "demo_key",
+  accountId: process.env.ABACATEPAY_ACCOUNT_ID || "demo_account",
+});
+
+export type { CreateBillingParams, BillingResponse };