[Forms/Events] Field Trips (Permission Slips + Payment)

Raised Sept 25. Field trips need a permission slip (ideally via the Custom Forms/E-Signed Waivers item) plus a payment collection tied to a specific one-time event, distinct from regular class tuition. Scope: create a field trip as an event, collect e-signed permission slips and payment from opted-in families, track who's signed/paid vs. not, before the trip date.