Tasks

Add OpenSpec scenarios for attendee-added trigger filtering and transformation.
Add a failing workflow-engine behavior test for transforming an added attendee through attendee_added.
Implement attendee-added workflow event, trigger filters, attendee.name condition/template value, and set_property attendee.name.
Apply attendee transformations from metadata/prompted starts, workflow add_attendee, screenshot OCR, and agent attendee tools.
Update workflow engine documentation.
Run focused tests plus openspec validate transform-added-attendees --strict.