feat(tip): customize first gift thank-you

docs/backend/FRONTEND_PAYMENT_API.md

@@ -264,9 +264,9 @@ Authorization: Bearer <TOKEN>
 {"orderId":"pay_xxx"}
 ```
 
-响应包含 `orderId`、`characterId`、`planId`、`productName`、`tipCount`、`poolIndex` 和可直接展示的完整 `message`。前端不再根据次数拼接文案，也不从订单状态读取感谢字段。
+响应包含 `orderId`、`characterId`、`planId`、`productName`、`tipCount`、`poolIndex` 和可直接展示的完整 `message`。`tipCount` 表示当前付款身份对同一商品的累计成功次数。
 
-Tip 成功页在文案加载期间立即确认支付成功；接口成功后按纯文本直接展示 `message`。接口失败时展示本地通用感谢语和 Retry，重试只重新请求 Tip Message，不重复轮询订单或创建订单。
+Tip 成功页在文案加载期间立即确认支付成功。`tipCount=1` 时展示固定首次咖啡文案并忽略后端 `message`；大于 1 时按纯文本直接展示 `message`。接口失败时展示本地通用感谢语和 Retry，重试只重新请求 Tip Message，不重复轮询订单或创建订单。
 
 ## 10. Provider 与状态边界
 

src/app/tip/__tests__/tip-screen.checkout.test.tsx

@@ -188,7 +188,36 @@ describe("TipScreen checkout", () => {
     expect(getCheckoutButton().disabled).toBe(true);
   });
 
-  it("shows the complete backend Tip message after payment", () => {
+  it("shows fixed copy for the first character Tip", () => {
+    mocks.payment = makePaymentState({
+      status: "paid",
+      isPaid: true,
+      orderStatus: "paid",
+      tipMessage: TipMessageResponseSchema.parse({
+        orderId: "pay_first",
+        characterId: "maya-tan",
+        planId: giftProduct.planId,
+        productName: giftProduct.planName,
+        tipCount: 1,
+        poolIndex: 4,
+        message: "This backend message is ignored for the first Tip.",
+      }),
+    });
+    renderScreen();
+
+    expect(container.textContent).toContain(
+      "Did you really just buy me a coffee?",
+    );
+    expect(container.textContent).toContain("That honestly made me smile.");
+    expect(container.textContent).toContain(
+      "I'll definitely think of you while I enjoy it.",
+    );
+    expect(container.textContent).not.toContain(
+      "This backend message is ignored for the first Tip.",
+    );
+  });
+
+  it("shows the backend message after the first Tip", () => {
     mocks.payment = makePaymentState({
       status: "paid",
       isPaid: true,
@@ -209,6 +238,9 @@ describe("TipScreen checkout", () => {
     expect(container.textContent).toContain(
       "This complete message came directly from the backend.",
     );
+    expect(container.textContent).not.toContain(
+      "Did you really just buy me a coffee?",
+    );
     expect(document.activeElement?.id).toBe("tip-success-title");
 
     act(() => getButton("Send another gift").click());

src/app/tip/tip-screen.tsx

@@ -191,6 +191,7 @@ export function TipScreen({
           "Your gift"
         }
         isMessageLoading={payment.isLoadingTipMessage}
+        tipCount={payment.tipMessage?.tipCount ?? null}
         message={payment.tipMessage?.message ?? null}
         messageError={payment.tipMessageError}
         splashHref={characterRoutes.splash}

src/app/tip/tip-success-view.tsx

@@ -12,11 +12,17 @@ import styles from "./tip-success-view.module.css";
 
 const GENERIC_TIP_SUCCESS_MESSAGE =
   "Thank you. Your gift made me smile.";
+const FIRST_TIP_TITLE = "Did you really just buy me a coffee?";
+const FIRST_TIP_MESSAGE = [
+  "That honestly made me smile.",
+  "I'll definitely think of you while I enjoy it.",
+] as const;
 
 export interface TipSuccessViewProps {
   characterName: string;
   characterAvatar: string;
   characterCover: string;
+  tipCount: number | null;
   giftImageSources: readonly string[];
   giftName: string;
   isMessageLoading: boolean;
@@ -31,6 +37,7 @@ export function TipSuccessView({
   characterName,
   characterAvatar,
   characterCover,
+  tipCount,
   giftImageSources,
   giftName,
   isMessageLoading,
@@ -41,6 +48,7 @@ export function TipSuccessView({
   onSendAgain,
 }: TipSuccessViewProps) {
   const titleRef = useRef<HTMLHeadingElement>(null);
+  const isFirstTip = tipCount === 1;
 
   useEffect(() => {
     titleRef.current?.focus({ preventScroll: true });
@@ -102,15 +110,21 @@ export function TipSuccessView({
             className={styles.title}
             tabIndex={-1}
           >
-            Thank you. Your gift made me smile.
+            {isFirstTip ? FIRST_TIP_TITLE : GENERIC_TIP_SUCCESS_MESSAGE}
           </h1>
           <div className={styles.copy}>
+            {isFirstTip
+              ? FIRST_TIP_MESSAGE.map((paragraph) => (
+                  <p key={paragraph}>{paragraph}</p>
+                ))
+              : (
                   <p>
                     {message ??
                       (isMessageLoading
                         ? "Your gift arrived. A thank-you note is on its way."
                         : GENERIC_TIP_SUCCESS_MESSAGE)}
                   </p>
+                )}
           </div>
 
           {messageError ? (