Sync & last-good

Each enabled source is fetched on a schedule (and can be force-synced by admins). A source is not required to succeed every wave.

Statuses

• Active — last fetch produced a usable pack
• Stale — fetch failed or converted empty; previous by-source file is still served
• Error — no last-good file to keep

Combined epg.xml includes stale last-good packs so one dead origin does not wipe that platform out of the guide. Programmes in a stale pack age until the origin recovers.

HTTP 304

If the origin says Not Modified, we keep the local pack. That is success, not a skip of the source.