feat: Add Baidu Qianfan V2 channel support #725

- Update channel constants to include Baidu V2 channel
- Create new Baidu V2 adaptor for relay
- Add Baidu V2 models and channel configuration
- Update relay adaptor to support Baidu V2 channel
- Modify web channel constants to include Baidu V2 option

relay/channel/deepseek/adaptor.go

@@ -29,7 +29,7 @@ func (a *Adaptor) Init(info *relaycommon.RelayInfo) {
 }
 
 func (a *Adaptor) GetRequestURL(info *relaycommon.RelayInfo) (string, error) {
-	return fmt.Sprintf("%s/chat/completions", info.BaseUrl), nil
+	return fmt.Sprintf("%s/v1/chat/completions", info.BaseUrl), nil
 }
 
 func (a *Adaptor) SetupRequestHeader(c *gin.Context, req *http.Header, info *relaycommon.RelayInfo) error {
@@ -54,7 +54,6 @@ func (a *Adaptor) ConvertEmbeddingRequest(c *gin.Context, info *relaycommon.Rela
 	return nil, errors.New("not implemented")
 }
 
-
 func (a *Adaptor) DoRequest(c *gin.Context, info *relaycommon.RelayInfo, requestBody io.Reader) (any, error) {
 	return channel.DoApiRequest(a, c, info, requestBody)
 }