Feature: Add Twitch EventSub sources to automation flows

[alsi-lawr]

Summary

Expose supported Twitch EventSub notifications as typed automation event sources, with subscription lifecycle, scope readiness, host isolation and duplicate-delivery handling.

Split from

This ticket splits the EventSub-trigger capability out of the “Necessary parity features” section in #1.

User outcome

A channel can start automations from Twitch activity such as going live, raids, subscriptions, cheers, follows and Hype Trains without writing code.

Scope

• Register typed flow sources for stream online/offline, follow, subscription, subscription gift, cheer, incoming raid, Hype Train begin/progress/end and supported chat notifications.
• Add source-specific configuration such as minimum cheer amount or raid viewer count.
• Map each EventSub payload to a bounded, documented automation context.
• Create/remove required EventSub subscriptions as host connections and enabled flows change.
• Show required OAuth scopes and current subscription readiness in the editor.
• Deduplicate EventSub delivery using Twitch message ID and retain the deduplication record for a bounded period.
• Handle subscription revocation and reconnect by disabling or warning affected flows rather than silently dropping events.
• Allow source definitions to be added incrementally without changing persisted flow contracts.

Design and constraints

• Twitch delivers EventSub notifications at least once; duplicate handling is mandatory.
• Only include fields required for automation and never expose access tokens or raw HTTP headers.
• Every subscription and event must resolve to exactly one BlokeBot host.
• Missing scopes or ineligible channel state must be actionable in the dashboard.
• The event receiver must acknowledge Twitch independently of downstream flow success.

Non-goals

• Supporting every EventSub type in the first implementation.
• Webhook transport if the existing runtime uses EventSub WebSocket.
• Allowing events to target other hosts.

Acceptance criteria

• The initial source set can be selected and configured in a flow.
• Required EventSub subscriptions are established and recovered with the host runtime.
• Duplicate Twitch message IDs do not start duplicate flow runs.
• Missing scopes and revoked subscriptions surface actionable readiness state.
• A failed flow does not prevent EventSub acknowledgement or other flows from running.
• Payload mapping, deduplication, subscription recovery and host isolation have automated tests.

Dependencies

• Define a typed automation event and action catalog
• Execute automation flows with conditions, delays and failure handling

References

• https://dev.twitch.tv/docs/eventsub
• https://dev.twitch.tv/docs/eventsub/eventsub-subscription-types/