feat: replace homepage with full-screen TUI interactive layout

[Copilot]

The homepage used VitePress's standard hero/features layout with CLI color overrides — visually styled but not structurally a TUI. This replaces it with a genuine TUI experience.

Changes

• TuiHome.vue (new): Full-screen fixed-position component with:

  • Split-pane layout — sidebar (nav menu + status panel) + main (ASCII art banner, terminal output block, action buttons)
  • Live clock in title bar; blinking block cursor in terminal prompt
  • Keyboard navigation: ↑↓/jk cycle menu, Enter opens selection, d/a/g as direct shortcuts, Tab wraps through items
  • Box-drawing characters (╔ ║ └ ─) throughout for authentic TUI chrome
  • Responsive: sidebar hidden on mobile, ASCII art hidden on small screens

• index.ts: Layout render function now checks frontmatter.layout === 'tuiHome' and returns TuiHome directly (no VitePress navbar/chrome); all other pages remain on the existing CLI-themed DefaultTheme

• index.md: Replaced hero/features frontmatter with single layout: tuiHome directive

╔═[ Lo7ong@hub ] ─── Technical Documentation System ─── [ 01:39:00 ]═╗
╠══ MENU ════╦══ WELCOME ═════════════════════════════════════════════╣
║ ▶ $ home   ║  ██╗      ██████╗ ...                                  ║
║   $ docs   ║  lo7ong@hub:~$ whoami                                  ║
║   $ api    ║  > Developer & Tech Enthusiast                         ║
║   ↗ github ║  lo7ong@hub:~$ █                                       ║
╠══ STATUS ══╣  [ ./documentation ] [ ./api-reference ] [ github ↗ ] ║
║ ● online   ╚════════════════════════════════════════════════════════╣
╚═[ ↑↓/jk: nav ][ Enter: open ][ d: docs ][ a: api ][ g: github ] ══╝

[Lo7ong]

new tui