Redesign homepage: dark hero, bold typography, cinematic screenshots

Kill the AI-template feel entirely. Navy hero that owns the viewport,
900-weight type at dramatic scale, staggered screenshot grid, page-load
choreography, and a differentiator statement with actual conviction.
No more off-white-with-rounded-cards generic SaaS energy.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>