Enhance AssistantConfig and pipeline for FastGPT integration

- Add new fields in AssistantConfig for FastGPT connection details, including `fastgpt_api_url`, `fastgpt_api_key`, and `fastgpt_app_id`.
- Update the pipeline to utilize the new FastGPT configuration, ensuring proper integration with external services.
- Introduce type handling for different assistant types, including support for realtime modes and external brain management.
- Refactor frontend components to include hints for FastGPT configuration inputs, improving user guidance during setup.

backend/services/pipecat/service_factory.py

@@ -132,16 +132,6 @@ def create_tts(cfg: AssistantConfig):
     )
 
 
-def create_services(cfg: AssistantConfig):
-    logger.info(
-        f"创建服务: stt={cfg.stt_interface_type}/{cfg.asr or config.STT_MODEL} "
-        f"llm={cfg.model or config.LLM_MODEL} "
-        f"tts={cfg.tts_interface_type}/{cfg.tts_model or config.TTS_MODEL} "
-        f"voice={cfg.voice or config.TTS_VOICE}"
-    )
-    return create_stt(cfg), create_llm(cfg), create_tts(cfg)
-
-
 def create_realtime_service(cfg: AssistantConfig):
     """Create a speech-to-speech service that owns STT, LLM, and TTS."""
     if cfg.realtime_interface_type == "stepfun-realtime":