actop 1.4.6

Docs

• README hero is now an animated GIF (images/actop-demo.gif) — actop live under an
  Ollama workload: stack layout, braille→block chart glyphs, then the watt-attributed
  process panel. The grid still (images/actop.png) is kept below as the fallback;
  the redundant stack/process stills (actop_stacked.png, actop_procs.png) were
  removed (the GIF demonstrates them in motion).
• Add CONTRIBUTING.md and a README ## Contributing section ("PRs and issues
  welcome") pointing to it; CLAUDE.md remains the full source of truth.
• Sync the design docs with the current repo/security posture:
  DESIGN-sdlc-cicd.md now documents Actions pinned to commit SHAs,
  branch-protection required status checks, and the enabled Dependabot
  alerts + security updates / private vulnerability reporting;
  DESIGN-system.md gains §5.8 documenting the TUI→docs capture skills
  (capture-tui-diagram, record-tui-gif).

Chore

• Add the record-tui-gif Claude Code skill (.agents/skills/record-tui-gif/):
  reproducible hero-GIF recording via vhs driven by a live GPU workload, so the
  capture can be refreshed after any TUI/layout change.