Migrate from Yarn to npm

[dominikbulaj]

The project should be migrated from Yarn to npm for package management. This will help standardize the workflow, simplify onboarding for new contributors, and improve compatibility with modern tooling.

Tasks:

• Remove yarn.lock and update documentation to reference npm commands
• Add or update package-lock.json using npm
• Update CI/CD scripts and developer guides to use npm
• Test installation and build processes to ensure a smooth migration

Please provide feedback or suggestions if there are any concerns regarding this migration.