fix: _openid为空时也应允许add()创建云端文档

之前当getOpenid未部署时，_doPush直接return，永远跳过了
db.collection().add()，导致集合无法自动创建、数据不能上云。
改为跳过locate+update但允许add()，CloudBase会自动填充_openid。

Co-Authored-By: Claude <noreply@anthropic.com>

utils/cloud.js

@@ -195,13 +195,12 @@ const _doPush = async () => {
           return
         }
       }
-    } else {
+    }  // else: openid is null — skip locate+update, go straight to add()
-      console.log('[cloud] _doPush no openid available, aborting (avoid duplicate add)')
-      return
-    }
 
-    // Reached only when we've positively confirmed no doc exists for our
+    // Reached when: (a) openid exists but no doc found, OR (b) openid is
-    // openid in the cloud — safe to add() the first document.
+    // null (getOpenid not deployed). In both cases add() is safe — CloudBase
+    // auto-populates _openid on document creation.
+    console.log('[cloud] _doPush adding new doc (openid=' + (openid || 'null') + ')')
     const res = await db.collection(DB_COLLECTION).add({ data })
     if (res && res._id) _docId = res._id
     if (res && res._openid) _openid = res._openid