feat(website): simplify homepage and animate Session architecture

[RyanLee-Dev]

Summary

The homepage has ten text-heavy sections that repeat architectural explanations. Reduce it to five focused sections with an interactive combination example, architecture image, Session animation, console screenshots and installation steps. Replace the long documentation list with four shortcuts.

Add a three-stage hand-drawn Session animation showing native execution, Core orchestration and multiple execution environments. It autoplays while visible, offers manual controls and respects reduced-motion preferences. Bundle Virgil with its OFL license, size diagram labels to fit their cards, and give section headings the hero’s display font with green italic accents.

Validation

• VitePress production build passed.
• Local browser preview inspected during the design iterations.
• git diff --check passed.
• Additional automated tests were not run, as requested.

Dependency

Based on #393 (ecosystem logo wall). Merge that PR first, then retarget this PR to main.

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