feat(translate): add Youdao as a new translation provider

The translate module previously only supported Baidu translation, and the
factory raised a bare RuntimeError for any other type. This change adds
Youdao Translation as a second provider and improves the factory's error
message.

Implementation details:
- New YoudaoTranslator class in translate/youdao/youdao_translate.py
- Implements Youdao's v3 SHA-256 signature scheme, including the
  truncate-input rule for queries longer than 20 characters
- Maps ISO 639-1 language codes to Youdao-specific codes
  (zh -> zh-CHS, zh-TW -> zh-CHT, others pass through)
- Differentiates network errors, API error codes, and empty translations
- factory.create_translator now lists the supported types in its
  RuntimeError message instead of failing silently
- Default config exposes youdao_translate_app_key and
  youdao_translate_app_secret

Adds 17 unit tests covering signature correctness, language code mapping,
input truncation edge cases, the full request/response flow, and factory
dispatch. All tests pass under Python 3.11.

config.py

@@ -123,10 +123,13 @@ available_setting = {
     "chat_start_time": "00:00",  # 服务开始时间
     "chat_stop_time": "24:00",  # 服务结束时间
     # 翻译api
-    "translate": "baidu",  # 翻译api，支持baidu
+    "translate": "baidu",  # 翻译api，支持baidu, youdao
     # baidu翻译api的配置
     "baidu_translate_app_id": "",  # 百度翻译api的appid
     "baidu_translate_app_key": "",  # 百度翻译api的秘钥
+    # youdao翻译api的配置
+    "youdao_translate_app_key": "",  # 有道翻译api的应用ID
+    "youdao_translate_app_secret": "",  # 有道翻译api的应用密钥
     # wechatmp的配置
     "wechatmp_token": "",  # 微信公众平台的Token
     "wechatmp_port": 8080,  # 微信公众平台的端口,需要端口转发到80或443