Build a video production workflow with OpenMontage that: 1) Takes a text description as input, 2) Researches relevant stock footage from free archives, 3) Generates missing clips using Veo/Kling APIs, 4) Composes soundtrack with Chirp3-HD, 5) Edits timeline with Remotion, 6) Renders final MP4. Include error handling for API rate limits and implement a cost calculator for each production step.