- Introduce CSS variables for theming in `global.css`
- Add `ThemeIcon` component for toggling light/dark modes
- Integrate theme initialization script in `BaseLayout` to prevent FOUC
- Update navigation, buttons, and tag styles for dark mode compatibility
- Configure Shiki for dual-theme syntax highlighting in `astro.config.mjs`
- Adjust link colors to accessible blue shades for both themes
- Install openssh-server and create SSH infrastructure in container
- Install rassumfrassum (LSP multiplexer) via Python venv
- Expose SSH port 2222 and mount user public key for TRAMP access
- Update compose.yml to map port 2222 and mount SSH_PUBKEY_PATH
- Document SSH setup and TRAMP /ssh: access method in README