- Add `discord.js-selfbot-v13` as a git submodule in `vendor/`
- Update `pnpm-workspace.yaml` to include the new submodule path
- Modify `.gitmodules` to track the submodule repository
- Change `discord.js-selfbot-v13` dependency in `package.json` to use `workspace:*`
- Create implementation and design documents for the submodule integration
