[Fix] Fast conversations receive duplicate canned PR status updates

[roomote-roomote]

​Opened on behalf of @mrubens. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

What changed

• Stop the terminal-status webhook fan-out from treating a Fast parent's Slack, Teams, Telegram, or Discord coordinates as an ordinary direct notification target.
• Match exact destination coordinates so non-Fast conversations and distinct child-task threads keep their canned status notifications.
• Preserve normal pull_request_status_changed platform-event delivery and Fast rendering, with a deterministic canned fallback only when Fast fails before posting any reply.
• Keep source-control event policy explicit: opened and terminal events use normal Fast interpretation, while feedback and conflict events retain their visibility-required presentation-only behavior.

Why this change was made

Fast child payloads inherit their parent conversation coordinates. The terminal webhook fan-out read those fields as an ordinary direct destination and posted its fixed was merged/closed by text into the Fast conversation, independently of the structured platform event that Fast also received.

Impact

Fast conversations receive the structured event and report it conversationally in session-owned wording without a preceding canned duplicate. Ordinary task conversations and dedicated child threads retain automated terminal updates, and failed Fast turns still produce one deterministic fallback when no reply was posted.

[roomote-community]

1 issue outstanding. See task

• Terminal delivery is dropped when the Fast-parent relay fails.
• Terminal notification is still lost when status-history recording fails before Fast delivery.

_{Reviewed eed7931}

[roomote-roomote]

Final revision: eed7931e stops notifyPullRequestTerminalStatus from posting canned status text when an inherited destination exactly matches the Fast parent conversation. Normal Fast pull_request_status_changed delivery and conversational rendering are preserved. Non-Fast targets and distinct child-task threads still receive direct automation, while a Fast-owned fallback posts only if inference fails before any reply.

Analogous event audit: PR feedback and conflicts already arbitrate Fast-parent delivery before direct fallback; PR opened, task-settled, child-message, artifact, and automation events have no parallel canned direct poster. CI failures flow through PR feedback and remain unchanged. Focused API/SDK suites, full lint/typechecking, and pre-push checks pass.