fix: update SQL verification queries to reference correct schemas

- Changed worker schema from worker.workers to pgflow.workers
- Updated schema reference for pgflow flows in verification query

Author: jumski

pkgs/website/src/content/docs/how-to/manual-installation.mdx

@@ -150,7 +150,7 @@ After completing the installation, verify it by running these queries:
 
 ```sql
 -- Verify worker schema
-SELECT * FROM worker.workers LIMIT 1;
+SELECT * FROM pgflow.workers LIMIT 1;
 
 -- Verify pgflow schema
 SELECT * FROM pgflow.flows LIMIT 1;