feat: 帖子分级置顶（板块/全站）与板块管理员置顶权限、消息管理权限调整

frontend/app/announcements/page.tsx

@@ -59,7 +59,7 @@ function FeaturedAnnouncement({ a, urlStyle }: { a: Announcement; urlStyle: UrlS
         </span>
         {a.pinned ? (
           <span className="badge-pin" title="置顶" aria-label="置顶">
-            <Pin size={12} fill="currentColor" strokeWidth={2.2} aria-hidden />
+            <Pin size={12} fill="none" strokeWidth={2} aria-hidden />
           </span>
         ) : null}
         <span className={`j13-anno-tag is-${a.tag_color}`}>{a.tag}</span>
@@ -93,7 +93,7 @@ function AnnouncementRow({ a, showDivider, urlStyle }: { a: Announcement; showDi
       <div className="flex items-center gap-2 flex-wrap">
         {a.pinned ? (
           <span className="badge-pin" title="置顶" aria-label="置顶">
-            <Pin size={12} fill="currentColor" strokeWidth={2.2} aria-hidden />
+            <Pin size={12} fill="none" strokeWidth={2} aria-hidden />
           </span>
         ) : null}
         <span className={`j13-anno-tag is-${a.tag_color}`}>{a.tag}</span>