ci: add copilot instructions

Author: andrzejnovak

.github/copilot-instructions.md

@@ -0,0 +1,35 @@
+## General Copilot Instructions
+
+- Commit messages and PR names should follow Conventional Commits specification (https://www.conventionalcommits.org/en/v1.0.0/)
+- Use present tense ("add feature" not "added feature")
+
+## Folder Structure
+
+- `/src/mplhep`: Contains the source code for project.
+- `/tests`: Contains tests.
+- `/docs`: Contains documentation for the project, including API specifications and user guides.
+- `/examples`: Is a joint folder for examples which are parts of both documentation and tests.
+
+## Coding Standards
+
+- Use single quotes for strings. Such that printed statements containing strings can use double quotes.
+- Follow PEP 8 guidelines for Python code.
+- Write docstrings for all public functions and classes using the NumPy/SciPy style.
+- Follow ruff configuration in pyproject.toml for linting and formatting
+- Use type hints where appropriate (mypy configuration available)
+- Run pre-commit hooks before committing
+
+
+## Testing Guidelines
+
+- For new features, add tests to the `tests/copilot` directory
+- When resolving issues, write tests into `tests/from_issues` directory
+- Use pytest-mpl for matplotlib-based tests that require visual comparison (most cases)
+- If you think it's useful, you can run the test suite with `python -m pytest -r sa --mpl --mpl-results-path=pytest_results -n 4` before submitting changes
+- Intentionally changed behaviours might require a new baseline generated as `pytest --mpl-generate-path=tests/baseline` if visual outputs change
+
+
+## Project-Specific Guidelines
+
+- Keep backward compatibility in mind for public APIs
+- Consider optional dependencies vs core requirements carefully

.github/copilot-setup-steps.yml

@@ -0,0 +1,52 @@
+name: "Copilot Setup Steps"
+
+# Automatically run the setup steps when they are changed to allow for easy validation, and
+# allow manual testing through the repository's "Actions" tab
+on:
+  workflow_dispatch:
+  push:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+
+jobs:
+  # The job MUST be called `copilot-setup-steps` or it will not be picked up by Copilot.
+  copilot-setup-steps:
+    runs-on: ubuntu-latest
+
+    # Set the permissions to the lowest permissions possible needed for your steps.
+    # Copilot will be given its own token for its operations.
+    permissions:
+      # If you want to clone the repository as part of your setup steps, for example to install dependencies, you'll need the `contents: read` permission. If you don't clone the repository in your setup steps, Copilot will do this for you automatically after the steps complete.
+      contents: read
+
+    # You can define any steps you want, and they will run before the agent starts.
+    # If you do not check out your code, Copilot will do this for you.
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v5
+
+      - name: Setup uv
+        uses: astral-sh/setup-uv@v5
+        with:
+          version: "latest"
+          python-version: ${{ matrix.python-version }}
+          enable-cache: true
+          cache-dependency-glob: "**/pyproject.toml"
+
+      - name: Requirements check
+        run: uv pip list
+
+      - name: Install core fonts
+        if: runner.os == 'Linux'
+        run: |
+          echo ttf-mscorefonts-installer msttcorefonts/accepted-mscorefonts-eula select true | sudo debconf-set-selections
+          sudo apt-get install ttf-mscorefonts-installer
+
+      - name: Install package
+        run: |
+          uv pip install -e ".[all]"
+          uv pip install pytest-github-actions-annotate-failures
+          uv pip list