Replace bw-serve/Ansible-based implementation with a clean rewrite:
- rbw CLI wrapper for listing entries and fetching credentials
- Rofi script-mode and fzf selectors with history-first sorting
- JSON-backed frecency history at ~/.cache/bw-menu/
- Clipboard support via wl-copy/xclip auto-detection
- uv + hatchling packaging with bw-menu entry point
