refactor: update project and add new options in pxtorem plugin

[felixicaza]

This pull request introduces a number of improvements to the project’s configuration, developer tooling, and documentation. The main focus is on modernizing and simplifying the workflows, adopting new linting and formatting tools, and enhancing the documentation for both the monorepo and the pxtorem plugin. Below are the most important changes, grouped by theme:

• CI/CD and Workflow Improvements: Updated GitHub Actions workflows (release.yml and tests.yml) to use the latest versions of actions, improved tag validation and parsing, added dependency caching, and improved changelog generation and publishing steps.
• Developer Tooling and Linting: Switched to custom shared linting and formatting configs (@felixicaza/eslint-config and @felixicaza/oxlint-config), simplifying eslint.config.ts and introducing a new oxlint.config.ts for type-aware linting.
• Documentation Enhancements: Revamped the main README.md for clarity, updated badges, improved package listing, and expanded contribution guidelines.
• New options: The plugin is now aligned to work with the same options as its PostCSS counterpart.

These changes collectively modernize the repository, improve developer experience, and provide clearer guidance for both contributors and users.