v1.10.0

Added

• --visual flag: the summarizer worker looks at 4 evenly-spaced, ephemeral
  keyframes so the summary can address on-screen content (diagrams, code,
  slides). Frames are extracted to a temp dir, read by the worker, then
  deleted — nothing is saved to the output folder. A "Visually checked at:"
  line in the summary records which timestamps were inspected. Requires ffmpeg;
  ignored in --full-transcript / --transcript-only modes. Adoption #3 from
  the claude-video roadmap.