Add v-phone-input component for enhanced phone number fields

Replace basic text fields with v-phone-input in CreateInterestModal and
InterestDetailsModal to provide country selection, validation, and better
UX for phone number entry. Includes US as default with preferred countries
list and search functionality.

plugins/v-phone-input.client.ts

@@ -0,0 +1,13 @@
+import { defineNuxtPlugin } from '#app'
+import { createVPhoneInput } from 'v-phone-input'
+import 'v-phone-input/dist/v-phone-input.css'
+
+export default defineNuxtPlugin((nuxtApp) => {
+  const vPhoneInput = createVPhoneInput({
+    defaultCountry: 'US',
+    preferredCountries: ['US', 'FR', 'ES', 'PT', 'GB'],
+    enableSearchingCountry: true,
+  })
+  
+  nuxtApp.vueApp.use(vPhoneInput)
+})