Code support format detection

CONTRIBUTING.md

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+# Contributing to Mole
+
+## Setup
+
+```bash
+# Install tools
+brew install shfmt shellcheck bats-core
+
+# Install git hooks (optional)
+./scripts/install-hooks.sh
+```
+
+## Development
+
+```bash
+# Format code
+./scripts/format.sh
+
+# Run tests
+./tests/run.sh
+
+# Check quality
+shellcheck -S warning mole bin/*.sh lib/*.sh
+```
+
+## Git Hooks
+
+Pre-commit hook will auto-format your code. Install with:
+```bash
+./scripts/install-hooks.sh
+```
+
+Skip if needed: `git commit --no-verify`
+
+## Code Style
+
+- Bash 3.2+ compatible
+- 4 spaces indent
+- Use `set -euo pipefail`
+- Quote all variables
+- BSD commands not GNU
+
+Config: `.editorconfig` and `.shellcheckrc`
+
+## Pull Requests
+
+1. Fork and create branch
+2. Make changes
+3. Format: `./scripts/format.sh`
+4. Test: `./tests/run.sh`
+5. Commit and push
+6. Open PR
+
+CI will check formatting, lint, and run tests.