feat: no-custom-classname adding @html-eslint/parser and alpinejs syntax support

[DianaSuvorova]

feat: no-custom-classname adding @html-eslint/parser support

Description

Currently, @angular-eslint/template-parser is recommended for HTML parsing, but it is not compatible with rules or plugins built on @html-eslint/parser, due to limitations discussed in:

eslint/eslint#18808

yeonjuan/html-eslint#211

This makes it difficult to use Tailwind-related ESLint rules in projects that use AlpineJS, since Alpine syntax (e.g. :class, x-cloak, x-transition) causes many false-positive errors.

Example from AlpineJS+Tailwind code (this one):

  10:9   error  Classname '{' is not a Tailwind CSS class!                        tailwindcss/no-custom-classname
  10:9   error  Classname ''border-neutral-200/60' is not a Tailwind CSS class!   tailwindcss/no-custom-classname
  10:9   error  Classname 'text-neutral-800'' is not a Tailwind CSS class!        tailwindcss/no-custom-classname
  10:9   error  Classname 'activeAccordion==id,' is not a Tailwind CSS class!     tailwindcss/no-custom-classname
  10:9   error  Classname ''border-transparent' is not a Tailwind CSS class!      tailwindcss/no-custom-classname
  10:9   error  Classname 'my-custom'' is not a Tailwind CSS class!               tailwindcss/no-custom-classname
  10:9   error  Classname 'activeAccordion!=id' is not a Tailwind CSS class!      tailwindcss/no-custom-classname
  10:9   error  Classname '}' is not a Tailwind CSS class!                        tailwindcss/no-custom-classname

This PR introduces a generic @html-eslint/parser-based visitor that:

• Works with both vanilla HTML and AlpineJS syntax
• Properly extracts Tailwind classnames from class and :class bindings
• Ignores Alpine directives like x-cloak, x-transition, etc.
• Avoids false positives without introducing any Alpine-specific logic

This change is non-breaking — existing usage with @angular-eslint/template-parser remains fully supported.

I plan to update other rules in the plugin to support @html-eslint/parser after initial feedback on this PR.

Thanks!

Type of change

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

Added tests using @html-eslint/parser with alpinejs and without

Test Configuration:

• OS + version: Sequoia 15.3.2
• NPM version: 8.19.2
• Node version: v18.12.0

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings