fix: improve logging for client disconnections in relay services

当客户端主动断开连接时，改为使用 INFO 级别记录而不是 ERROR 级别，
因为这是正常情况而非错误。

- ccrRelayService: 区分客户端断开与实际错误
- claudeConsoleRelayService: 区分客户端断开与实际错误
- claudeRelayService: 区分客户端断开与实际错误
- droidRelayService: 区分客户端断开与实际错误

src/services/ccrRelayService.js

@@ -448,7 +448,14 @@ class CcrRelayService {
       // 更新最后使用时间
       await this._updateLastUsedTime(accountId)
     } catch (error) {
-      logger.error(`❌ CCR stream relay failed (Account: ${account?.name || accountId}):`, error)
+      // 客户端主动断开连接是正常情况，使用 INFO 级别
+      if (error.message === 'Client disconnected') {
+        logger.info(
+          `🔌 CCR stream relay ended: Client disconnected (Account: ${account?.name || accountId})`
+        )
+      } else {
+        logger.error(`❌ CCR stream relay failed (Account: ${account?.name || accountId}):`, error)
+      }
       throw error
     } finally {
       // 📬 释放用户消息队列锁