feat: enhance StripePaymentDialog with document handling and portal rendering

src/app/subscription/components/stripe-payment-dialog.tsx

@@ -4,7 +4,8 @@
  *
  * 后端当前返回 PaymentIntent clientSecret，因此这里直接用它完成前端确认。
  */
-import { useState, type FormEvent } from "react";
+import { useEffect, useState, type FormEvent } from "react";
+import { createPortal } from "react-dom";
 import {
   Elements,
   PaymentElement,
@@ -35,31 +36,44 @@ export function StripePaymentDialog({
   onClose,
   onConfirmed,
 }: StripePaymentDialogProps) {
-  if (!stripePromise) {
-    return (
-      <div className={styles.overlay} role="alertdialog" aria-modal="true">
-        <div className={styles.dialog}>
-          <div className={styles.header}>
-            <h2 className={styles.title}>Payment unavailable</h2>
-            <p className={styles.content}>
-              Stripe publishable key is not configured for this build.
-            </p>
-          </div>
-          <div className={styles.actions}>
-            <button
-              type="button"
-              className={`${styles.button} ${styles.primary}`}
-              onClick={onClose}
-            >
-              OK
-            </button>
-          </div>
+  useEffect(() => {
+    if (typeof document === "undefined") return;
+
+    const prevOverflow = document.body.style.overflow;
+    const handleKeyDown = (event: KeyboardEvent) => {
+      if (event.key === "Escape") onClose();
+    };
+
+    document.body.style.overflow = "hidden";
+    document.addEventListener("keydown", handleKeyDown);
+
+    return () => {
+      document.body.style.overflow = prevOverflow;
+      document.removeEventListener("keydown", handleKeyDown);
+    };
+  }, [onClose]);
+
+  const dialog = !stripePromise ? (
+    <div className={styles.overlay} role="alertdialog" aria-modal="true">
+      <div className={styles.dialog}>
+        <div className={styles.header}>
+          <h2 className={styles.title}>Payment unavailable</h2>
+          <p className={styles.content}>
+            Stripe publishable key is not configured for this build.
+          </p>
+        </div>
+        <div className={styles.actions}>
+          <button
+            type="button"
+            className={`${styles.button} ${styles.primary}`}
+            onClick={onClose}
+          >
+            OK
+          </button>
         </div>
       </div>
-    );
-  }
-
-  return (
+    </div>
+  ) : (
     <div
       className={styles.overlay}
       role="dialog"
@@ -95,6 +109,10 @@ export function StripePaymentDialog({
       </div>
     </div>
   );
+
+  if (typeof document === "undefined") return null;
+
+  return createPortal(dialog, document.body);
 }
 
 function StripePaymentForm({