fix(attach): 附件改回浏览器下载通道，仅按钮触发且不再误报已开始

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/app/globals.css

@@ -1767,15 +1767,12 @@ body {
   text-decoration: none;
   color: inherit;
   font: inherit;
-  cursor: pointer;
+  cursor: default;
   border: 1px solid var(--line);
   background: var(--panel);
   box-shadow: var(--shadow-sm);
   transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s, background 0.15s;
 }
-a.j13-att-card:hover {
-  color: inherit;
-}
 .j13-att-card:hover {
   transform: translateY(-1px);
   box-shadow: var(--shadow);
@@ -1800,13 +1797,7 @@ a.j13-att-card:hover {
   border-color: color-mix(in srgb, var(--ok) 46%, var(--line));
 }
 .j13-att-card.is-busy {
-  cursor: wait;
-}
-.j13-att-card:disabled {
-  opacity: 0.58;
-  cursor: not-allowed;
-  transform: none;
-  box-shadow: var(--shadow-sm);
+  opacity: 0.92;
 }
 .j13-att-card.is-fresh {
   animation: j13-att-unlock 0.7s ease-out;
@@ -1923,11 +1914,25 @@ a.j13-att-card:hover {
   font-weight: 600;
   line-height: 1;
   flex-shrink: 0;
-  pointer-events: none;
+  cursor: pointer;
   border: 1px solid var(--line-2);
   background: var(--panel);
   color: var(--ink);
   white-space: nowrap;
+  font-family: inherit;
+  text-decoration: none;
+  appearance: none;
+}
+a.j13-att-cta:hover {
+  color: var(--ink);
+}
+.j13-att-cta:hover:not(:disabled):not(.is-primary) {
+  border-color: var(--accent);
+  color: var(--accent);
+}
+.j13-att-cta:disabled {
+  opacity: 0.5;
+  cursor: not-allowed;
 }
 .j13-att-cta.is-primary {
   border-color: transparent;
@@ -1936,6 +1941,10 @@ a.j13-att-card:hover {
   box-shadow: 0 1px 2px rgba(16, 24, 40, 0.12),
     0 2px 8px color-mix(in srgb, var(--accent) 26%, transparent);
 }
+.j13-att-cta.is-primary:hover:not(:disabled) {
+  background: var(--accent-hi);
+  color: var(--accent-on);
+}
 .j13-att-pay {
   display: flex;
   flex-direction: column;

frontend/components/PostAttachments.tsx

@@ -1,10 +1,14 @@
 "use client";
 
-import { useEffect, useState } from "react";
+import { useEffect, useState, type ReactNode } from "react";
 import Link from "next/link";
 import { useRouter } from "next/navigation";
 import { Check, Coins, Loader2, Paperclip } from "lucide-react";
-import { apiDownloadPostAttachment, type PostAttachment } from "@/lib/api";
+import {
+  apiDownloadPostAttachment,
+  postAttachmentDownloadURL,
+  type PostAttachment,
+} from "@/lib/api";
 import { toast } from "@/lib/toast";
 import Modal from "@/components/Modal";
 
@@ -64,7 +68,8 @@ function fileKind(name: string, mime: string): "image" | "archive" | "doc" | "me
   return "file";
 }
 
-function saveBlob(blob: Blob, filename: string) {
+/** 把已拿到的文件交给浏览器下载栏（付费首次须先 fetch 才能处理 402） */
+function triggerBrowserDownload(blob: Blob, filename: string) {
   const url = URL.createObjectURL(blob);
   const a = document.createElement("a");
   a.href = url;
@@ -73,28 +78,17 @@ function saveBlob(blob: Blob, filename: string) {
   document.body.appendChild(a);
   a.click();
   a.remove();
-  URL.revokeObjectURL(url);
+  window.setTimeout(() => URL.revokeObjectURL(url), 30_000);
 }
 
-function AttachmentFace({
+function AttachmentMeta({
   a,
   unlocked,
-  busy,
-  guestPaid,
 }: {
   a: PostAttachment;
   unlocked: boolean;
-  busy: boolean;
-  guestPaid: boolean;
 }) {
   const paid = a.price_points > 0;
-  const cta = guestPaid
-    ? "登录后下载"
-    : busy
-      ? "处理中…"
-      : paid && !unlocked
-        ? "支付下载"
-        : "下载";
   return (
     <>
       <span className="j13-att-type" data-kind={fileKind(a.name, a.mime)} aria-hidden>
@@ -123,11 +117,6 @@ function AttachmentFace({
           <span className="j13-att-price-unit">免费</span>
         )}
       </span>
-      <span className={`j13-att-cta${paid && !unlocked ? " is-primary" : ""}`}>
-        {busy ? <Loader2 size={14} className="animate-spin" aria-hidden /> : null}
-        {!busy && unlocked && paid ? <Check size={14} aria-hidden /> : null}
-        {cta}
-      </span>
     </>
   );
 }
@@ -158,9 +147,9 @@ export default function PostAttachments({
 
   const isUnlocked = (a: PostAttachment) => a.unlocked || unlockedIds.includes(a.id);
 
-  const download = async (a: PostAttachment) => {
+  /** 付费未解锁：先确认再 fetch，避免积分不足时整页 JSON；成功后交给浏览器下载栏 */
+  const downloadPaid = async (a: PostAttachment) => {
     if (busyId != null) return;
-    const firstPaid = a.price_points > 0 && !isUnlocked(a);
     setBusyId(a.id);
     try {
       const res = await apiDownloadPostAttachment(postId, a.id, a.name);
@@ -173,15 +162,11 @@ export default function PostAttachments({
         toast(res.error || "下载失败");
         return;
       }
-      saveBlob(res.blob, res.filename || a.name);
+      triggerBrowserDownload(res.blob, res.filename || a.name);
       setPending(null);
-      if (firstPaid) {
-        setUnlockedIds((prev) => (prev.includes(a.id) ? prev : [...prev, a.id]));
-        setFreshId(a.id);
-        toast("已解锁并开始下载", "ok");
-      } else {
-        toast("已开始下载", "ok");
-      }
+      setUnlockedIds((prev) => (prev.includes(a.id) ? prev : [...prev, a.id]));
+      setFreshId(a.id);
+      toast("已解锁", "ok");
       router.refresh();
     } catch {
       toast("下载失败，请稍后重试");
@@ -190,13 +175,9 @@ export default function PostAttachments({
     }
   };
 
-  const onActivate = (a: PostAttachment) => {
+  const onPayCta = (a: PostAttachment) => {
     if (busyId != null) return;
-    if (a.price_points > 0 && !isUnlocked(a)) {
-      setPending(a);
-      return;
-    }
-    void download(a);
+    setPending(a);
   };
 
   return (
@@ -217,10 +198,15 @@ export default function PostAttachments({
           const label = guestPaid
             ? `登录后下载 ${a.name}，需 ${formatPoints(a.price_points)} 积分`
             : paidLocked
-              ? `下载 ${a.name}，需 ${formatPoints(a.price_points)} 积分`
-              : a.price_points > 0
-                ? `下载 ${a.name}（已解锁）`
-                : `下载 ${a.name}（免费）`;
+              ? `支付 ${formatPoints(a.price_points)} 积分下载 ${a.name}`
+              : `下载 ${a.name}`;
+          const ctaText = guestPaid
+            ? "登录后下载"
+            : busy
+              ? "处理中…"
+              : paidLocked
+                ? "支付下载"
+                : "下载";
           const className = [
             "j13-att-card",
             a.price_points > 0 ? "is-paid" : "",
@@ -230,27 +216,43 @@ export default function PostAttachments({
           ]
             .filter(Boolean)
             .join(" ");
-          const face = (
-            <AttachmentFace a={a} unlocked={unlocked} busy={busy} guestPaid={guestPaid} />
-          );
+          const ctaClass = `j13-att-cta${paidLocked || guestPaid ? " is-primary" : ""}`;
+          const nativeHref = postAttachmentDownloadURL(postId, a.id);
+          let cta: ReactNode;
+          if (guestPaid) {
+            cta = (
+              <Link href={loginHref} className={ctaClass} aria-label={label}>
+                {ctaText}
+              </Link>
+            );
+          } else if (paidLocked) {
+            cta = (
+              <button
+                type="button"
+                className={ctaClass}
+                aria-label={label}
+                aria-busy={busy || undefined}
+                disabled={busyId != null}
+                onClick={() => onPayCta(a)}
+              >
+                {busy ? <Loader2 size={14} className="animate-spin" aria-hidden /> : null}
+                {ctaText}
+              </button>
+            );
+          } else {
+            cta = (
+              <a href={nativeHref} className={ctaClass} aria-label={label} download={a.name}>
+                {unlocked && a.price_points > 0 ? <Check size={14} aria-hidden /> : null}
+                {ctaText}
+              </a>
+            );
+          }
           return (
             <li key={a.id}>
-              {guestPaid ? (
-                <Link href={loginHref} className={className} aria-label={label}>
-                  {face}
-                </Link>
-              ) : (
-                <button
-                  type="button"
-                  className={className}
-                  aria-label={label}
-                  aria-busy={busy || undefined}
-                  disabled={busyId != null}
-                  onClick={() => onActivate(a)}
-                >
-                  {face}
-                </button>
-              )}
+              <article className={className}>
+                <AttachmentMeta a={a} unlocked={unlocked} />
+                {cta}
+              </article>
             </li>
           );
         })}
@@ -287,7 +289,7 @@ export default function PostAttachments({
               disabled={busyId != null || !pending}
               onClick={() => {
                 if (!pending) return;
-                void download(pending);
+                void downloadPaid(pending);
               }}
             >
               {busyId != null ? (