refactor: AES 请求体改用 SimApiOneFieldRequest 序列化，去掉手拼字符串

- aesQuery/aesSignQuery：{"data":"..."} 手拼 → SimApiOneFieldRequest<String>
  经 SimApiUtil.json 序列化（对齐 C# new SimApiOneFieldRequest<string>{...}）
- SimApiOneFieldRequest<T> 恢复带参构造（构造请求用）

src/helpers/SimApiHttpClient.cj

@@ -86,7 +86,7 @@ public open class SimApiHttpClient {
             target = "${target}?${name}=${appId}"
         }
         let encrypted = aesEncrypt(body)
-        let req = "{\"data\":\"${encrypted}\"}"
+        let req = SimApiUtil.json(Some(SimApiOneFieldRequest<String>(encrypted)))
         return query<T>(target, req)
     }
 
@@ -100,7 +100,7 @@ public open class SimApiHttpClient {
      */
     public func aesSignQuery<T>(url: String, body: String, queries!: HashMap<String, String> = HashMap<String, String>()): T {
         let encrypted = aesEncrypt(body)
-        let req = "{\"data\":\"${encrypted}\"}"
+        let req = SimApiUtil.json(Some(SimApiOneFieldRequest<String>(encrypted)))
         return signQuery<T>(url, body: req, queries: queries)
     }