feat(api): 接入微信登录并原生实现咨询域（ECR-049/050）

小程序可在 Go 上完成微信手机号登录、测评、预约和下单，不再反代 Java。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/config.example.yaml

@@ -24,6 +24,23 @@ admin:
   bootstrap_username: admin
   bootstrap_password: "change-me" # override in config.local.yaml; never commit secrets
 
+# Mini-program WeChat login (never commit real secrets)
+wechat:
+  app_id: ""
+  secret: ""
+
+# Legacy Java (ECR-049, unused after ECR-050 native consult)
+java:
+  base_url: ""
+  internal_key: ""
+
+# WeChat JSAPI pay. Empty = mock pay params (dev).
+pay:
+  app_id: ""
+  mch_id: ""
+  api_key: ""
+  notify_url: "https://h5.yuxingu.com.cn/psy/api/v1/psychic/pay/notify"
+
 # jwt:
 #   secret: ""
 # payment: