feat: Add @data-fair/lib-vuetify-events with notification queue component

[albanm]

Summary

• Introduce a new publishable package @data-fair/lib-vuetify-events (lib-vuetify/) providing reusable Vuetify components for embedding events features in other
  apps
• Add DfNotificationQueue component — a bell button with badge that opens a dropdown menu listing the user's recent notifications (with i18n support for EN/FR)
• Integrate the component into the dev page for testing and add an e2e Playwright test covering subscription creation, event push, and notification display
• Clean up legacy v-iframe / iframe-resizer code from ui/src/main.ts

Details

The DfNotificationQueue component:

• Shows a bell icon with a badge indicating unread notification count
• Opens a v-menu dropdown listing up to 10 recent notifications with title, date, body, and sender avatar
• Handles unauthenticated state with a login prompt
• Accepts an eventsUrl prop to target any events API instance

Package is published as @data-fair/lib-vuetify-events (currently at v0.2.1) with peer dependencies on Vue 3.5+, Vuetify 4+, @data-fair/lib-vuetify, and
@data-fair/lib-vue.

Test plan

• e2e test: bell button visible on dev page
• e2e test: notification appears in dropdown after event is sent with matching subscription