Add dynamic variable support to Assistant model and related components

- Introduce dynamic variable definitions in AssistantConfig and Assistant models, allowing for flexible prompt customization.
- Implement validation for dynamic variable names and types in the schema.
- Update backend services and routes to handle dynamic variables in assistant configurations and runtime processing.
- Enhance frontend components to support dynamic variable definitions, including a new editor for managing variables.
- Add tests to ensure proper functionality and validation of dynamic variables in various scenarios.

frontend/src/lib/api.ts

@@ -183,6 +183,7 @@ export type Assistant = {
   knowledgeRetrievalConfig: KnowledgeRetrievalConfig;
   toolIds: string[];
   prompt: string;
+  dynamicVariableDefinitions: Record<string, DynamicVariableDefinition>;
   apiUrl: string;
   apiKey: string;
   appId: string;
@@ -190,6 +191,12 @@ export type Assistant = {
   updatedAt?: string | null;
 };
 
+export type DynamicVariableDefinition = {
+  type: "string" | "number" | "boolean";
+  required: boolean;
+  default: string | number | boolean | null;
+};
+
 export type KnowledgeRetrievalConfig = {
   mode: "automatic" | "on_demand";
   topN: number;
@@ -307,6 +314,7 @@ export type HttpToolDefinition = {
     headers: Record<string, string>;
     parameters: ToolParameter[];
     body: Record<string, unknown>;
+    dynamicVariableAssignments: Record<string, string>;
   };
 };