@unhead/vue 2.1.15, ajv 8.20.0, vitest 4.1.6, vite 8.0.13, vue 3.5.34,
vue-router 5.0.7, @vue/test-utils 2.4.10, happy-dom 20.9.0,
@vitejs/plugin-vue 6.0.7. Adds vue + vue-router to devDependencies so
the dev-time install pins to the wanted lockfile version (they were
peer-only before, which left them un-bumpable by `npm install <pkg>@<ver>`).

Two majors deferred: @unhead/vue 3.x, sharp 0.34.x.

Tests: 588 passing.