feat: redesign website and studio experience

[KingDoxik]

Summary

• redesign the marketing landing and pricing pages with a new visual and motion system
• refresh Studio workflows for experiments, feature flags, paywalls, and placements
• expand the design documentation and component previews
• update supporting backend RPC behavior and waitlist gating

Impact

This delivers a more cohesive public website and Studio experience, with clearer navigation and richer management workflows.

Validation

• git diff --check origin/preview...HEAD
• publication boundary check passed
• @voidhash/www typecheck passed
• @voidhash/backend typecheck passed
• backend tests: 168 passed; the authorization-matrix test still expects the previous experiment RPC operation names

[github-actions]

Thank you for following the naming conventions for pull request titles! 🙏

[greptile-apps]

Too many files changed for review. (339 files found, 100 file limit)

Bypass the limit by tagging @greptile-apps to review.

[github-actions]

Install the packages built from d142584:

@voidhash/paywalls

pnpm add @voidhash/paywalls@https://pkg.voidha.sh/paywalls/d142584

@voidhash/node

pnpm add @voidhash/node@https://pkg.voidha.sh/node/d142584

@voidhash/web

pnpm add @voidhash/web@https://pkg.voidha.sh/web/d142584

voidhash-cli

pnpm add voidhash-cli@https://pkg.voidha.sh/cli/d142584

@voidhash/react-native

pnpm add @voidhash/react-native@https://pkg.voidha.sh/react-native/d142584

Internal workspace deps (generated-clients, shared, studio) are published at the same sha and resolved automatically.

Replace the sha with pr-116 or the branch name to always get the latest build of this PR.