refactor(backend): split log files into separate file

lib/helpers.ts

@@ -9,7 +9,7 @@ export function json(content: unknown) {
 export const isValidUrl = (urlString: string) => {
   try {
     return Boolean(new URL(urlString));
-  } catch (e) {
+  } catch (_e) {
     return false;
   }
 };
@@ -87,6 +87,8 @@ export const createStreamResponse = () => {
   };
 };
 
+export type StreamResponse = ReturnType<typeof createStreamResponse>;
+
 export function debounce<T extends (...args: Parameters<T>) => void>(
   this: ThisParameterType<T>,
   fn: T,