Css File Linting With Probe Support

Real-time ESLint integration with auto-fix.

Unique: Adds experimental CSS linting support through ESLint plugins rather than implementing a dedicated CSS linter; marked as 'probe' support, indicating preliminary implementation that may require additional configuration or plugins.

vs others: More integrated than separate CSS linters because it uses ESLint configuration and rules; less mature than dedicated CSS linters (e.g., Stylelint) because CSS support is experimental and scope is unclear.