Migrate to ESLint 10 (blocked upstream on eslint-config-next)

[CyKiller]

Blocked upstream — not actionable in this repo yet.

ESLint 10 fails during rule loading, inside eslint-config-next:

TypeError: Error while loading rule 'react/display-name':
  contextOrFilename.getFilename is not a function
    at resolveBasedir (web/node_modules/eslint-config-next/node_modules/eslint-plugin-react/lib/util/version.js:31)
    at detectReactVersion (…/version.js:85)

eslint-config-next bundles its own eslint-plugin-react, and that copy calls an API ESLint 10 removed. It fails while linting web/eslint.config.mjs itself — before reaching a single source file — so no config change on our side can work around it. It needs an eslint-config-next release carrying a compatible plugin.

Raised and closed as #63. The ESLint major is now ignored on the /web ecosystem so it is not re-raised weekly; minor and patch continue to flow.

Unblock condition

A Next.js release whose eslint-config-next supports ESLint 10. Then:

1. Remove the eslint major ignore from the /web entry in .github/dependabot.yml
2. Let dependabot re-raise, and confirm the Web (lint + type-check + tests + build) job passes