Estimate Cost

Estimate a generation from its model and billable duration in seconds. Supply a finite positive duration and, optionally, a finite positive fps (defaults to 30). No media is fetched and no generation is created. POST /v2/generate/estimate-cost is an alias of this endpoint. Invalid request fields return 400. If the billing calculation rejects the duration or frame rate, it returns 422 cost_estimate_unavailable without price fields.