fix: 修复 IMAP 邮件内容获取问题

- 使用 body: '.' 获取邮件完整内容，替代 source（某些 IMAP 服务器不支持）
- 添加详细的 fetch 结果日志，记录返回的字段名
- 改进邮件获取失败时的日志输出

src/app/api/monitor/scan-emails/route.ts

@@ -208,13 +208,21 @@ async function scanEmails(
         }
 
         try {
-          const msg = await client.fetchOne(uid, { source: true, uid: true }, { uid: true })
-          if (!msg || !('source' in msg) || !(msg as any).source) {
-            console.log(`[Scan] 邮件 ${uid} 无内容，跳过`)
+          // 使用 body 获取邮件内容，source 在某些 IMAP 服务器上可能不返回内容
+          const msg = await client.fetchOne(uid, { uid: true, bodyStructure: true, body: '.' }, { uid: true })
+          if (!msg) {
+            console.log(`[Scan] 邮件 ${uid} 获取失败，跳过`)
             continue
           }
 
-          const parsed = await simpleParser((msg as any).source as Buffer)
+          // 优先使用 source，其次使用 body
+          const rawSource = (msg as any).source || (msg as any).body
+          if (!rawSource) {
+            console.log(`[Scan] 邮件 ${uid} 无内容，跳过 (keys: ${Object.keys(msg).join(',')})`)
+            continue
+          }
+
+          const parsed = await simpleParser(rawSource as Buffer)
           const subject = parsed.subject || ''
           const date = parsed.date ? formatBeijingTime(parsed.date) : formatBeijingTime()
           const msgId = parsed.messageId || String(uid)