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.

frontend/src/lib/api.ts

@@ -180,6 +180,7 @@ export type Assistant = {
   visionModelResourceId: string | null;
   modelResourceIds: Partial<Record<ModelType, string>>;
   knowledgeBaseId: string | null;
+  knowledgeRetrievalConfig: KnowledgeRetrievalConfig;
   toolIds: string[];
   prompt: string;
   apiUrl: string;
@@ -189,6 +190,12 @@ export type Assistant = {
   updatedAt?: string | null;
 };
 
+export type KnowledgeRetrievalConfig = {
+  mode: "automatic" | "on_demand";
+  topN: number;
+  scoreThreshold: number;
+};
+
 export type AssistantUpsert = Omit<Assistant, "id" | "updatedAt">;
 
 export const assistantsApi = {