Make YouTube thumbnails for a summit session

A webhook starts it from a session record in Airtable. It marks the thumbnail status as AI Writing, creates a placeholder row in your creatives table and splits the session's thumbnail titles into one item per title.

For each title it builds an image prompt that copies the style of a reference thumbnail you linked, places the guest's cutout headshot and, for a Host + Guest layout, the host's headshot too. A code step shapes the request for the chosen image model, then a Fal.ai job runs and the workflow polls until it finishes. The images are attached to the creative row, set to To Do, and the session status changes to AI Complete. Costs are logged.