Use when the user wants to build a 60-second animated product demo video that plays in the browser and is recordable to .webm. Triggers on "/create-feature-demo", "make a feature demo video", "build product walkthrough", "create demo video for [product]", "record a product demo". Requires marketing-brief.md from /setup-marketing-suite to exist. Builds a single self-contained HTML file with timeline-driven scene composition, real product UI mockups extracted from the codebase, captions, optional voiceover or sound cues, and an in-browser screen-recording flow that exports to .webm.
