Refresh frontend tooling devDependencies and drop dead packages

[alistair3149]

Result of a package.json dependency audit requested by @alistair3149.
Context: the NeoWiki frontend (resources/ext.neowiki) manifest + lockfile, the vite/vitest/eslint/stylelint configs, MediaWiki 1.43 foreign-resources.yaml (which fixes the externalized vue/codex/pinia pins), and live npm registry metadata.
_{Written by Claude Code, Opus 4.8}

Dev-only updates to resources/ext.neowiki. Runtime libs (vue, @wikimedia/codex, pinia) stay pinned to the versions MediaWiki 1.43 provides at runtime (they are externalized in the Vite build).

• Align with eslint-config-wikimedia 0.32.4: @stylistic/eslint-plugin ^2.8.0 -> ^3.1.0 and eslint-plugin-unicorn ^55 -> ^56.0.1 (both still support ESLint 8, which the wikimedia config pins us to).
• types-mediawiki ^1.8.0 -> ^2.0.0 (the v2 removed aliases are unused in our source).
• jsdom ^25 -> ^29.1.1 (+ @types/jsdom ^28). Its stricter, more spec-compliant selector engine required replacing fragile div > div > :is(a, span) selectors in RelationDisplay.spec.ts that relied on the query scope element itself matching the first div.
• @types/node ^22 -> ^24 to match the Node 24 CI/runtime.
• axios -> ^1.18.1, less -> ^4.6.7 (in-range refresh).
• Replace the unmaintained npm-run-all with its drop-in fork npm-run-all2 ^8.0.4.
• Declare stylelint directly (previously only present transitively via the config).
• Remove dead devDependencies: @types/dompurify (no dompurify dep or usage) and sass-embedded (no SCSS in the project).

Pin @vue/test-utils to 2.4.6: 2.4.11's attachTo path calls Vue 3.5's app.onUnmount, which throws against our pinned Vue 3.4.27.

vite/vitest are upgraded in a separate PR.

Verified with make tsci (test, build, lint) on Node 24.