fix(ai): DeepSeek 余额按官方 balance_infos 解析

/user/balance 返回的是 {is_available, balance_infos[]}，没有顶层 data，
旧实现永远解析出 None，连接测试会显示「余额 None CNY」。同时补全
TotHost 预设平台，新环境初始化后即可直接配 whmcs-panel。

app/adapters/ai.py

@@ -34,12 +34,20 @@ class DeepSeekAdapter(_AIBase):
     BASE = "https://api.deepseek.com"
 
     def _balance(self) -> AccountInfo:
-        data = self._get(self.BASE + "/user/balance").get("data", {})
+        # 官方响应为 {is_available, balance_infos: [{currency,total_balance,...}]}，
+        # 没有顶层 data；同时兼容旧版 data.total_balance 形态。
+        data = self._get(self.BASE + "/user/balance")
+        infos = data.get("balance_infos") or []
+        info = next((i for i in infos if i.get("currency") == "CNY"), infos[0] if infos else {})
+        if not info and isinstance(data.get("data"), dict):
+            info = data["data"]
         try:
-            total = float(data.get("total_balance")) if data.get("total_balance") is not None else None
+            total = float(info.get("total_balance")) if info.get("total_balance") is not None else None
         except (TypeError, ValueError):
             total = None
-        return AccountInfo(balance=total, currency="CNY", raw=data)
+        return AccountInfo(
+            balance=total, currency=info.get("currency") or "CNY", raw=data
+        )
 
     def test_connection(self) -> dict:
         try: