Fallback invalid CoinPay checkout amounts (#42)

Co-authored-by: Codex Microtask Operator <codex-microtask@example.com>

apps/logicsrc-web/contract/logicsrc-web.contract.test.ts

@@ -221,6 +221,29 @@ describe("POST /api/hire-us/coinpay-checkout", () => {
     expect(body.payment.checkout_url).toBe("https://checkout.stripe.test/card-only");
   });
 
+  it("falls back when CoinPay returns an invalid checkout amount", async () => {
+    process.env.COINPAY_API_KEY = "cp_test_key";
+    process.env.COINPAY_API_URL = "https://coinpayportal.example";
+    process.env.COINPAY_BUSINESS_ID = "business-123";
+    process.env.COINPAY_ELIGIBILITY_MERCHANT_ID = "merchant-123";
+
+    vi.spyOn(globalThis, "fetch").mockImplementation(async (input) => {
+      const url = typeof input === "string" ? input : input.toString();
+      if (url.includes("/api/payments/merchant-eligibility")) {
+        return jsonResponse({ success: true, accepts_card: true, accepts_crypto: false, chains: [] });
+      }
+      return jsonResponse({ success: true, payment: { id: "pay_123", amount_usd: "not-a-number" } }, 201);
+    });
+
+    const response = await coinpayCheckout(
+      new NextRequest("http://localhost/api/hire-us/coinpay-checkout", { method: "POST", body: "{}" })
+    );
+    const body = await response.json();
+
+    expect(response.status).toBe(201);
+    expect(body.payment.amount_usd).toBe(250);
+  });
+
   it("does not create checkout when no payment rail is available", async () => {
     process.env.COINPAY_API_KEY = "cp_test_key";
     process.env.COINPAY_API_URL = "https://coinpayportal.example";

apps/logicsrc-web/src/app/api/hire-us/coinpay-checkout/route.ts

@@ -70,12 +70,13 @@ export async function POST(request: NextRequest) {
     }
 
     const payment = (payload.payment as Record<string, unknown>) || {};
+    const amountUsd = Number(payment.amount_usd ?? payment.amount ?? 250);
     return json(
       {
         success: true,
         payment: {
           id: payment.id,
-          amount_usd: Number(payment.amount_usd ?? payment.amount ?? 250),
+          amount_usd: Number.isFinite(amountUsd) ? amountUsd : 250,
           payment_method: payment.stripe_checkout_url ? "card" : paymentRail.method,
           currency: payment.currency ?? payment.blockchain ?? paymentRail.blockchain ?? paymentRail.currency,
           crypto_amount: payment.amount_crypto ?? payment.crypto_amount ?? null,