- Add terminal-chat-interface component with dual-panel layout
- Implement light/dark mode with next-themes
- Reorganize shadcn components to shadcn-io subdirectory
- Add custom retro icons (security, terminal, bot, etc.)
- Update color scheme with oklch values for both themes
- Add theme toggle and Gitea repository link
- Include corner bracket accents and grid/scan line effects
- Fix hydration mismatch for session time display
