Add knowledge retrieval configuration to Assistant model and related components

- Introduce new fields for knowledge retrieval configuration in AssistantConfig and Assistant models, including mode, top_n, and score_threshold.
- Implement KnowledgeRetrievalConfig schema with validation for top_n.
- Update backend services and routes to handle knowledge retrieval settings.
- Enhance frontend components to support knowledge retrieval configuration, including a new dialog for advanced settings.
- Add tests for knowledge retrieval configuration validation and description generation.

backend/schemas.py

@@ -17,6 +17,7 @@ RuntimeMode = Literal["pipeline", "realtime"]
 ModelType = Literal["LLM", "ASR", "TTS", "Realtime", "Embedding", "Agent"]
 AssistantType = Literal["prompt", "workflow", "dify", "fastgpt", "opencode"]
 TurnEndStrategy = Literal["silence", "smart_turn"]
+KnowledgeRetrievalMode = Literal["automatic", "on_demand"]
 ToolType = Literal["end_call", "http"]
 ToolStatus = Literal["active", "archived", "draft"]
 ToolParameterType = Literal["string", "number", "integer", "boolean", "object", "array"]
@@ -62,6 +63,19 @@ class TurnConfig(CamelModel):
     turn_detection: TurnDetectionConfig = Field(default_factory=TurnDetectionConfig)
 
 
+class KnowledgeRetrievalConfig(CamelModel):
+    mode: KnowledgeRetrievalMode = "automatic"
+    top_n: int = Field(default=5, ge=-1)
+    score_threshold: float = Field(default=0.0, ge=0.0, le=1.0)
+
+    @field_validator("top_n")
+    @classmethod
+    def validate_top_n(cls, value: int) -> int:
+        if value == 0:
+            raise ValueError("topN 必须为 -1 或大于 0")
+        return value
+
+
 # 各 type 允许的瘦字段(其余字段写入时清零,防止跨类型脏数据)
 ALLOWED_FIELDS: dict[str, set[str]] = {
     "prompt": {"prompt"},
@@ -85,6 +99,9 @@ class AssistantUpsert(CamelModel):
 
     model_resource_ids: dict[ModelType, str] = Field(default_factory=dict)
     knowledge_base_id: str | None = None
+    knowledge_retrieval_config: KnowledgeRetrievalConfig = Field(
+        default_factory=KnowledgeRetrievalConfig
+    )
     tool_ids: list[str] = Field(default_factory=list)
 
     # 瘦类型专属(真列);按 type 取用,无关字段写入时清零