feat: add optional handler property to IRegisteredApiSchema and update OpenApiRegistry to use it

Author: NoOne7135

adminforth/servers/express.ts

@@ -465,7 +465,7 @@ class ExpressServer implements IExpressHttpServer {
           request_schema: schema.request,
           response_schema: schema.response,
           meta: schema.meta,
-          handler: async () => null,
+          handler: undefined as never,
         });
       });
     });

adminforth/servers/openapi.ts

@@ -59,6 +59,7 @@ class OpenApiRegistry implements IOpenApiRegistry {
       request_schema: options.request_schema,
       response_schema: responseSchema,
       meta: options.meta,
+      handler: options.handler,
     };
     const compiledRoute: CompiledApiSchema = {
       ...route,

adminforth/types/Back.ts

@@ -98,6 +98,7 @@ export interface IRegisteredApiSchema {
   meta?: Record<string, unknown>;
   request_schema?: AnySchemaObject;
   response_schema?: AnySchemaObject;
+  handler?: (input: IAdminForthEndpointHandlerInput) => void | Promise<any>;
 }
 
 export interface IAdminForthApiValidationError {