Pipeline: Create, Fill, and Organize

Complete a multi-step file management workflow.

Tasks:
1. Create `docs/` directory
2. Create `docs/intro.md` with "# Welcome"
3. Create `docs/api.md` with "# API Reference"
4. Copy `docs/intro.md` to `docs/intro-backup.md`
5. Move `docs/api.md` to `docs/reference/api.md` (create `docs/reference` first)
6. Remove `docs/intro-backup.md`