feat(github): add copilot instructions

Author: maximehuran

.github/copilot-instructions.md

@@ -0,0 +1,21 @@
+# Copilot Instructions for SyliusMediaManagerPlugin
+
+## General Guidelines
+- Follow the Sylius 2.x and Symfony 7.x best practices for PHP code.
+- Use strict types and type hints wherever possible.
+- All new code must be PSR-12 compliant and pass PHPStan and ECS checks.
+- Use dependency injection for all services and avoid using service locators.
+- Write clear, concise, and well-documented code.
+- Use English for all code comments, variable names, and documentation.
+
+## Commit Messages
+- Use clear, descriptive commit messages in English.
+- Reference related issues or tickets when applicable.
+
+## Pull Requests
+- Ensure all checks pass before requesting review.
+- Provide a clear description of the changes and testing steps.
+
+---
+
+For more details, refer to the project README and Sylius/Symfony documentation.