Add xbanxia.cc parser support

[s4daharu]

Summary

Add first-class parser support for \xbanxia.cc\.

This adds a dedicated \XbanxiaParser\ for:

• chapter list extraction
• chapter title/content extraction
• cover image extraction
• metadata extraction
• site-specific cleanup

It also updates the contributor checklist items by adding \s4daharu\ to \package.json\ and the Credits section in \
eadme.md\.

Validation

• \
  pm run lint\ passes
• produced:
  • \eslint/WebToEpub1.0.12.2.xpi\
  • \eslint/WebToEpub1.0.12.2.zip\
  • \eslint/packed.js\
• \XbanxiaParser\ QUnit coverage passes locally

Notes

The full \unitTest/Tests.html\ suite still shows 6 unrelated pre-existing \DOMPurify is not defined\ failures in existing tests. This PR is intentionally scoped to \xbanxia.cc\ parser support plus the contribution-guide credit updates.

[dteviot]

@s4daharu

Thank you very much for your contribution. Note, generally, I only bother to add unit tests for code that needs to do "complicated" logic. For example, for this parser, I'd only bother to add a unit test for the extractSubject() function. The rest of the functions are so simple that just running WebToEpub against a web page and then checking the UI (and the generated Epub) is usually sufficient.

That said, it would be nice if you included the URLs of the Table of Contents and a couple of chapters you tested the parser against, (Mostly if someone says "It's broken", then we have something to go back to, to look for breakages.