Enhance knowledge base functionality and integrate S3 storage support

- Add new models for `KnowledgeDocument` and `KnowledgeChunk` to manage document ingestion and chunking.
- Implement S3-compatible storage integration for knowledge documents, allowing for file uploads and retrieval.
- Introduce API endpoints for managing knowledge bases and documents, including creation, deletion, and searching.
- Update frontend components to support knowledge base configuration and document management, improving user interaction.
- Enhance backend services for knowledge processing and retrieval, ensuring robust handling of document statuses and errors.

backend/services/config_resolver.py

@@ -137,6 +137,7 @@ async def resolve_runtime_config(
         enableInterrupt=assistant.enable_interrupt,
         turnConfig=assistant.turn_config or {},
         tools=await _tools_for(session, assistant),
+        knowledge_base_id=assistant.knowledge_base_id,
         # workflow 图:仅 workflow 类型非空,引擎据此启用图驱动对话
         graph=(assistant.graph or {}) if assistant.type == "workflow" else {},
         # 外部托管类型连接信息(DB 存真 key,直接注入)