refactor: upgrade ESLint and migrate its plugins to v9

[wellwelwel]

Here's the popular PR with thousands of changed lines 😅

There is no change in the actual files, except for ESLint applying the auto fixes, including Prettier's rules (nothing else), while migrating ESLint and its respective plugins to their latest versions.

For years, lint-stage never performed formatting before commits, which is why so many files were affected. I'll open a separate PR removing this dependency since it's not actually used in practice.

Also, you can follow all breaking changes from ESLint in Migrate to v9.x documentation.

---

CodeQL

It's interesting to note that CodeQL will notify about two warnings, since a comma has been removed from the line in question for each warning.

If this is indeed a problem to be addressed, I don't see this PR as the ideal place for it, since it's exclusively for lint and format rules and its apply.

However, Copilot suggested it:

const charMap = {
  '<': '\\u003C',
  '>': '\\u003E',
  '/': '\\u002F',
  '\\': '\\\\',
  '\b': '\\b',
  '\f': '\\f',
  '\n': '\\n',
  '\r': '\\r',
  '\t': '\\t',
  '\0': '\\0',
  '\u2028': '\\u2028',
  '\u2029': '\\u2029'
};

function escapeUnsafeChars(str) {
  return str.replace(/[<>\b\f\n\r\t\0\u2028\u2029]/g, x => charMap[x]);
}

• It might be worth checking a dedicated PR for this.

[wellwelwel]

I also took care to check each PR opened one by one:

From 49 valid PRs (not bots):

• 38 inevitably need rebasing due to conflicts.
• In addition, 7 requires investigation and 3 requires discussion of ideias or implementations approaches.
• Most of them are inactive for years.

I carefully create a label for each of them, which is where each link above leads.

---

The recent #3451 PR was not impacted ✨