Upgrade eslint 9 → 10 and @eslint/js 9 → 10

[strickvl]

Context

Dependabot PR #216 included eslint 9.39.2 → 10.1.0 and @eslint/js 9.39.2 → 10.0.1. These are major version bumps that were deferred from the safe batch update in #219/#220.

What to expect

ESLint 10 is a major release that may include:

• Changes to rule APIs and defaults
• Config format updates (flat config changes)
• Dropped support for older Node.js versions
• New/changed rule behaviors

Both eslint and @eslint/js should be upgraded together since they're tightly coupled.

Steps

1. Create a branch and bump both eslint and @eslint/js to latest v10
2. Run npm run lint and fix any new lint errors
3. Update eslint config if needed
4. Verify CI passes

Labels

dependencies