… rules

`draftwise init` now writes `.draftwise/constitution.md` on both the brownfield and greenfield paths. Five stable section headings — Voice, Spec language, Edge case discipline, Project conventions, Domain glossary — that every drafting prompt (`new`, `tech`, `tasks`, `scan`, `explain`, greenfield Phase 3) tells the host coding agent to read before drafting and apply by name. `scan` and the greenfield Phase 3 additionally instruct the agent to refine the **Project conventions** section from observed code / chosen stack, replacing the placeholder.

This replaces the role that `src/ai/prompts/principles.js` and `src/ai/prompts/spec-quality.js` used to play before the api-mode drop. Those modules injected collaboration + spec-language rules into every system prompt; with synthesis moved entirely into the host coding agent, the rules now live in the user's repo as a markdown file the agent reads on each call. The file is user-editable and version-controlled, so changes are reviewable and travel with the repo.

Reader utility at `src/utils/constitution.js` (`readConstitution(cwd)` returns null on ENOENT, propagates other errors); template at `src/utils/constitution-template.js`. Every prompt that references the file says "skip silently if absent" — back-compat for projects that ran `init` before this feature landed.

CLAUDE.md and README.md updated end-to-end (key design principles, src/utils list, "What gets installed" tree). CHANGELOG.md `[Unreleased] ### Added` entry documents the rationale and the section structure.