Introduce comprehensive documentation of HAPI's Seamless Handoff feature:
- README: Add Seamless Handoff to Features section
- how-it-works: Add complete Seamless Handoff guide with local/remote modes and switching workflow
- quick-start: Add Seamless Handoff link to Next steps
- AppShowcase: Add third card featuring "Switch Freely" mode switching capability
- Locales: Update English and Chinese translations for showcase content
- Support both local and remote server deployment
- Add direct public IP access option for remote servers
- Remove tunnel requirement messaging
- Organize remote access options with details sections
- Initialize VitePress documentation site with config, index, and guides
- Add guides for quick-start, installation, PWA, how-it-works, FAQ, and why HAPI
- Update .gitignore to exclude VitePress cache directory
- Update logo.svg with actual icon from web/public/icon.svg
- Simplify README.md with link to full installation guide
- Remove redundant WHY_NOT_HAPPY.md (content migrated to why-hapi guide)
weishu