feat(groups): chat_group 补 6 群主/建群列 + 复合PK迁移修复 + 存量回填

对齐云客员工聊天窗口·微信群 tab(2026-08-25 真机验证 raw_json 键):
- ChatGroup 加列 owner_name/owner_wxid/owner_alias/owner_avatar/
  friend_count/create_time(全 nullable)
- scraper _normalize_chat_group 同名提取;createTime 兼容 ms-int 与
  'YYYY-MM-DD HH:mm:ss'(smoke.db 实测 1105 行全为后者),复用
  _parse_add_time 归一 ms-epoch
- 迁移 099ac2097fa2:加 6 列 + 修复 Task1 评审遗留 drift——PK 由单列
  room_id 变更为复合 (room_id, channel, owner_account_id) 且
  owner_account_id NOT NULL(对齐模型 8a99940;smoke.db 1105 行无 NULL,
  未兜底编造数据);SQLite 走 batch 重建(copy_from 显式旧结构),
  MySQL 渲染为直接 ALTER(离线 --sql 已验证)
- 回填脚本 scripts/backfill_chat_group_fields.py(幂等,逐列只补空);
  smoke.db 实跑 backfilled 1105/1105,重跑 0/1105
- GroupOut 加 6 字段(model_validate 自动输出,路由无改)

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

yunke-server/app/api/schemas.py

@@ -182,6 +182,13 @@ class GroupOut(BaseModel):
     member_count: int | None = None
     message_count: int | None = None
     last_chat_time: int | None = None
+    # 群主/建群补充列(2026-08-25 对齐云客微信群 tab;scraper/回填脚本提取)
+    owner_name: str | None = None
+    owner_wxid: str | None = None
+    owner_alias: str | None = None
+    owner_avatar: str | None = None
+    friend_count: int | None = None
+    create_time: int | None = None  # 建群时间 ms epoch
     raw_json: dict[str, Any] | None = None