Google Sheets: column "Status" changes to "Completed"
↓ N8N trigger: Google Sheets → row updated
↓ N8N action: POST /api/v1.0/invitations
event_id: [marathon event ID]
badge_id: [finisher badge ID]
recipient_name: "Leonardo Silva"
recipient_email: "leonardo@email.com"
reason: "Completed 42km in 1:42:32"
↓ That's Me: certificate issued, email sent to Leonardo
↓ That's Me webhook: certificate.accepted fires when Leonardo accepts it
↓ N8N trigger: webhook received
↓ N8N action: update Google Sheets row with certificate URL