feat(website): add all-capability cinema scroll

[Natsummerance]

Summary

• Add a continuous all-capability cinema stage behind the homepage feature story.
• Render real recording frames with interpolated frame blending, velocity ghosting, slice displacement, particles, grid, and scanlines.
• Move nine semantic capability panels through the scroll range and link each one to its localized canonical answer page.
• Share one frame store across both film sections to avoid duplicate network/memory costs.
• Preserve reduced-motion behavior as a static accessible feature list.

Approvals

Design / accessibility-performance / release engineering: 9.91 / 9.87 / 9.84; final decision meeting 9.88 (capability_cinema_approval.json).

Validation

• npm run verify:release: green; capability cinema contracts pass.
• Browser smoke: 44/44 routes passed, zero failures.
• Homepage cinema progress reaches 0.85+, rail transform moves, and all nine panels render.