Add an optional owners[] field to groups (super-admin only). When set,
only webhook events whose repository owner or organization login matches
enter that group's routes; empty owners means no restriction, keeping
existing routes backward compatible.
- types: Group.owners?, groups.ts groupAcceptsOwners()
- webhook.ts eventOwners() extracts repo owner + org login
- discord.ts dispatch skips routes whose group rejects the event owner
- admin-routes.ts validateGroups() validates owners list
Gateway is now an opt-in feature (DISCORD_GATEWAY_ENABLED); when disabled,
messages are delivered via the Discord REST API (discord-rest.ts) instead of
the Durable Object. Record per-route delivery results (send-log.ts) for the
WebUI. Configure assets binding, DO sqlite migration and cron trigger.
