chore: add release workflow (commitlint, husky, lint-staged, release-it)

docs/decisions/0003-release-workflow.md

@@ -0,0 +1,36 @@
+# 0003 — Release workflow
+
+Date: 2026-06-01
+Status: accepted
+
+## Context
+
+The project needed a consistent, enforced standard for commit messages, changelog generation, versioning, and GitHub releases — especially important since both humans and AI agents (Claude Code, Codex) commit to the repo.
+
+## Decision
+
+- **commitlint** (`@commitlint/config-conventional`) enforces conventional commit format at the `commit-msg` git hook
+- **husky** v9 wires the hooks; `prepare` installs them on `pnpm install`
+- **lint-staged** runs prettier + eslint on staged files at the `pre-commit` hook
+- **release-it** + `@release-it/conventional-changelog` manages the full release cycle:
+  - bumps `package.json` version (semver)
+  - generates/prepends to `CHANGELOG.md`
+  - creates a signed git tag (`v{version}`)
+  - creates a GitHub Release with the generated notes
+  - pushes the tag and commit
+
+Release commands:
+
+- `pnpm release` — interactive (prompts for increment type)
+- `pnpm release:patch` / `:minor` / `:major` — non-interactive
+- `pnpm release:dry` — preview without writing anything
+- Requires `GITHUB_TOKEN` in env for GitHub Release creation
+
+Conventional commit types: `feat`, `fix`, `refactor`, `docs`, `test`, `chore`, `perf`, `ci`, `revert`
+
+## Consequences
+
+- Every commit is validated; bad format is rejected immediately
+- CHANGELOG.md is auto-generated from commit history — no manual upkeep
+- Releases are reproducible: one command, idempotent output
+- `chore`, `ci`, `test` commits are hidden in the changelog; `feat`, `fix`, `perf`, `refactor`, `docs` are surfaced