Add Duckweed, a local multi-pane workspace for coding agents

[MusicMaster4]

Please consider adding Duckweed to the tools or developer-workflow section.

Duckweed is a local-first desktop terminal workspace for running real shells, coding-agent CLIs, tests, and Git review in one window. It supports side-by-side interfaces for Claude Code, Codex CLI, Cursor Agent, Grok CLI, and OpenCode, while keeping the underlying CLIs and project files on the user's machine.

• Stable releases: https://github.com/MusicMaster4/Duckweed/releases/latest
• Platforms: Windows x64, macOS universal, Linux x64
• License: Duckweed Source-Available License 1.0, not an OSI-approved open-source license
• No Duckweed account or hosted workspace

The README has a short quick start and platform troubleshooting guide for first-time users.