Refactor embedding configuration to remove local model support, transitioning to a unified remote API approach. Update environment variables and documentation accordingly. Enhance error handling in the orchestrator and related modules to reflect these changes. This update simplifies the embedding process and improves overall system reliability.

backend/config/settings.py

@@ -16,10 +16,8 @@ class Settings(BaseSettings):
     temperature: float = 0.3
     max_tokens: int = 4096
 
-    # Embedding配置
-    embedding_model_path: str = ""  # 仅本地 Embedding 时使用；默认走远程 API
+    # Embedding / 向量检索（编码走远程 API，见 OPENAI_* / MODELSCOPE_* 等）
     vector_dim: int = 2048
-    use_local_embedding: bool = True
 
     # Schema配置
     schema_dir: str = "./data/schemas"