[rebeccathedev]

Summary

• migrate the frontend from Vue 2.7 to Vue 3.5 and Vue Router 4
• update vue-loader and switch from vue-template-compiler to @vue/compiler-sfc
• move global plugins, mixins, Axios, and Bootstrap helpers onto the Vue 3 application instance
• replace removed Vue 2 reactivity and lifecycle APIs
• upgrade PortalVue and vue-toast-notification and move the onboarding wizard to its Vue 3 package
• retain hash-based routing so existing browser URLs continue to work

Validation

• npm test — 17 passing
• npx webpack --mode production — successful (existing bundle-size warnings only)
• npm ls confirms a single Vue 3.5 runtime and no Vue 2 compiler or plugins
• npm audit — 0 vulnerabilities
• git diff --check