Journey Realtime

It reads the Realtime section from 02-plan.md, asks you to confirm, then delegates to the realtime skill which calls manage_realtime to configure each table. The skill skips entirely if your plan has no realtime needs and marks itself (n/a). One thing to watch: it will happily enable realtime on tables whose RLS policies aren't ready yet, so clients connect but see nothing. The preflight check ensures your app_id exists and docs are current before touching any live configuration.