docs: add CONTRIBUTING.md with setup, style, and PR guidelines

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: AliceLJY

CONTRIBUTING.md

@@ -0,0 +1,66 @@
+# Contributing to ClawTeam-OpenClaw
+
+Thanks for your interest in contributing! This guide helps you get started quickly.
+
+## Setup
+
+```bash
+git clone https://github.com/win4r/ClawTeam-OpenClaw.git
+cd ClawTeam-OpenClaw
+pip install -e ".[dev]"
+```
+
+## Development workflow
+
+1. **Create a branch** from `main`:
+   ```bash
+   git checkout -b feat/your-feature main
+   ```
+
+2. **Make your changes** — keep PRs focused on one thing.
+
+3. **Run checks** before committing:
+   ```bash
+   ruff check clawteam/ tests/
+   pytest tests/
+   ```
+
+4. **Submit a PR** against `main`. Fill in the PR template.
+
+## Code style
+
+- **Linter**: [ruff](https://docs.astral.sh/ruff/) — `ruff check` must pass with zero warnings.
+- **Line length**: 100 characters (configured in `pyproject.toml`).
+- **Imports**: sorted by ruff (`I` rules). Run `ruff check --fix` to auto-sort.
+- **Python**: 3.10+ — use `from __future__ import annotations` if needed.
+
+## PR guidelines
+
+- **One PR = one feature/fix.** Don't bundle unrelated changes.
+- **Add tests** for new functionality. We have 450+ tests — keep the bar high.
+- **Keep diffs small.** PRs over 500 lines are hard to review. If your feature is large, split it into sequential PRs.
+- **Update CHANGELOG.md** under `[Unreleased]` for user-facing changes.
+
+## Testing
+
+```bash
+pytest tests/                    # full suite
+pytest tests/test_foo.py -v     # single file
+pytest -k "test_name"           # single test
+```
+
+## Project structure
+
+```
+clawteam/
+├── cli/           # CLI commands (typer)
+├── spawn/         # Agent spawn backends (tmux, subprocess)
+├── team/          # Team lifecycle, mailbox, tasks
+├── templates/     # Team templates
+├── transport/     # File-based message transport
+└── workspace/     # Workspace overlay management
+```
+
+## Need help?
+
+Open an issue or check existing ones — we're happy to guide first-time contributors.