Feature/add cypress configuration

[darkmavis1980]

Description

This PR adds comprehensive Stylelint and Cypress E2E testing support to the @hs-web-team/eslint-config-node package.
The Cypress configuration has been migrated from Webpack to esbuild for improved performance and native TypeScript support. Additionally, the Cypress configuration targets Cypress 15, supports both JavaScript and TypeScript consumer projects natively via esbuild (no additional loaders or configuration required), and bundles all preprocessor dependencies so consumers only need to install cypress itself.

Currently, the baseline cypress config lives in the eslint-config-browser package and the DX e2e test suites consume this config file. However, this package will be deprecated in the future which is why we are creating the config file in this package with the final goal of migrating all test suites to use this config.

Summary of Changes 📋

Stylelint Support

• Added .stylelintrc.json with shared configuration for SCSS/CSS linting
• Extends stylelint-config-standard-scss with HubSpot-specific customizations
• Created comprehensive documentation in examples/stylelint-usage.md

Cypress E2E Testing

• Added cypress.config.js with shared Cypress configuration
• Migrated from Webpack to esbuild for faster bundling and native TypeScript support
• Specify Cypress 15 and corresponding compatible test dependencies
• Includes Cucumber preprocessor setup with esbuild integration
• HubSpot CMS-specific utilities (getDevBaseUrl(), getBaseUrls())
• Created detailed documentation in examples/cypress-usage.md

Documentation

• Updated README.md with Stylelint and Cypress setup instructions
• Updated CLAUDE.md with architecture details and usage patterns

Dependencies

• Added peer dependencies for Cypress and Stylelint
• Upgraded globals and typescript-eslint packages
• Added esbuild-related packages for Cypress preprocessing

Files Changed

• .stylelintrc.json - New Stylelint configuration
• cypress.config.js - New Cypress configuration with esbuild
• examples/stylelint-usage.md - New Stylelint documentation
• examples/cypress-usage.md - New Cypress documentation
• CLAUDE.md - Updated architecture documentation
• README.md - Updated setup instructions
• package.json - Added peer dependencies and updated dependencies
• package-lock.json - Dependency lock file updates

Testing

• Tested Stylelint configuration in a downstream project
• Tested Cypress configuration in a downstream project
• Verified esbuild preprocessor works with TypeScript
• Verified Cucumber preprocessor integration
• Validated documentation accuracy

Production Checklist

• All documentation is accurate and up-to-date
• Peer dependencies are correctly specified
• Migration path from Webpack to esbuild is documented
• Example configurations are tested and working
• Breaking changes (if any) are documented in migration guide