docs: add root AGENTS.md with conventional commit conventions (#10)

Adds agent instructions for the projectuner repo itself (not the
template) covering repo structure, PR title format, Release Please
types, and the release workflow.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: davidpoblador

AGENTS.md

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+# Agent Instructions
+
+Copier template that scaffolds git projects using the bare repo + worktree pattern.
+
+## Repository structure
+
+```
+copier.yml           Copier template configuration
+template/            Template files copied to new projects
+  setup.sh.jinja     Post-copy scaffolding script
+  .mise/tasks/       Mise task scripts for worktree management
+  AGENTS.md          Agent instructions for scaffolded projects
+scripts/
+  convert-to-worktree  Converts an existing git clone to worktree structure
+```
+
+## PR title conventions
+
+This project uses **Release Please** for automated versioning and changelog generation.
+PR titles must follow **conventional commit format** because they become the commit message
+after squash-merge.
+
+### Format
+
+```text
+<type>[optional scope]: <description>
+```
+
+### Types
+
+| Type | Changelog section | Version bump |
+|------|-------------------|--------------|
+| `feat:` | Features | MINOR |
+| `fix:` | Bug Fixes | PATCH |
+| `docs:` | Documentation Updates | PATCH |
+| `chore:` | Miscellaneous Chores | PATCH |
+| `refactor:` | Code Refactoring | PATCH |
+| `test:` | Tests | PATCH |
+| `perf:` | Performance Improvements | PATCH |
+| `ci:` | CI/CD Changes | PATCH |
+| `build:` | Build System | PATCH |
+| `style:` | Styling Changes | PATCH |
+
+### Breaking changes
+
+Add `!` after the type to signal a breaking change (MAJOR version bump):
+
+```text
+feat!: remove deprecated API
+```
+
+### Release workflow
+
+1. Merge a PR with a conventional title
+2. Release Please creates/updates a release PR with version bump and changelog
+3. Merge the release PR when ready to publish
+4. Release Please creates a GitHub release with a git tag

CLAUDE.md

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+AGENTS.md