fix: 图标上传不再手动设置 multipart Content-Type

避免缺少 boundary 导致后端读不到 icon_key；失败时展示具体 key。

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

src/views/miniapp/MiniappAssets.vue

@@ -408,6 +408,10 @@ async function loadPindao() {
 
 async function uploadIcon(file, iconKey) {
   if (!file?.raw) return
+  if (!iconKey) {
+    ElMessage.error('缺少 icon_key')
+    return
+  }
   uploadingKey.value = iconKey
   try {
     const fd = new FormData()
@@ -415,17 +419,17 @@ async function uploadIcon(file, iconKey) {
     fd.append('file', file.raw)
     fd.append('icon_key', iconKey)
     fd.append('action', 'upload')
-    const res = await request.post(JITUAN_API.miniappIconManage, fd, {
-      headers: { 'Content-Type': 'multipart/form-data' },
-    })
+    // 不要手动设 Content-Type，否则缺 boundary，后端可能读不到 icon_key
+    const res = await request.post(JITUAN_API.miniappIconManage, fd)
     if (res.code === 0) {
       ElMessage.success('上传成功')
       await loadIcons()
     } else {
-      ElMessage.error(res.msg || '上传失败')
+      ElMessage.error(res.msg || `上传失败(${iconKey})`)
     }
-  } catch {
-    ElMessage.error('上传失败')
+  } catch (e) {
+    const msg = e?.response?.data?.msg || e?.message || '上传失败'
+    ElMessage.error(`${msg} [${iconKey}]`)
   } finally {
     uploadingKey.value = ''
   }