Install promptbook in a project

You are setting up @markbrutx/promptbook in a user's project so they can assemble prompts deterministically from reusable fragments. There is no promptbook init CLI — install is a small set of file edits + one or two npm installs. Do them, then verify with promptbook ls and promptbook lint.

Mental model — what you are creating

promptbook reads one folder ("a book") of plain files:

prompts/
├─ fragments/    *.md   - reusable micro-prompts (text + YAML frontmatter)
├─ rules/       *.yaml  - one declarative composition per file (base order + when-rules)
├─ code-prompts/ *.yaml - optional, builders that stay in code
├─ fixtures/    *.json  - optional, eval cases / named variants
└─ promptbook.json     - config (promptsDir, lint, eval)