docs(edge-worker): Update documentation for monitoring feature

Clarify description of monitoring and heartbeats in edge worker documentation

pkgs/pgflow.dev/src/content/docs/edge-worker/how-it-works.mdx

@@ -16,7 +16,7 @@ import { Aside } from "@astrojs/starlight/components";
 Under the hood, it wraps [Supabase Background Tasks](https://supabase.com/docs/guides/functions/background-tasks) and adds a lot of useful features:
 
 - retries with delays
-- monitoring and heartbeats
+- monitoring (heartbeats)
 - concurrency control
 - horizontal scaling (by deploying multiple edge functions for the same queue)