fix(SharePoster): 将缩略图宽度固定为400px以避免重复处理

@@ -109,7 +109,7 @@ function build_cdn_thumbnail(src, width) {
     try {
         const u = new URL(url, window.location.origin)
         if (u.hostname === 'cdn.ipadbiz.cn') {
-            const param = `imageMogr2/thumbnail/${Math.max(100, Math.round(width))}x/strip/quality/70`
+            const param = `imageMogr2/thumbnail/400x/strip/quality/70`
             const has_mogr = url.includes('imageMogr2')
             // 若已有 imageMogr2，直接返回原地址，避免重复追加造成不确定行为
             if (!has_mogr) {