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.

components/CreateInterestModal.vue

@@ -76,13 +76,15 @@
                   ></v-text-field>
                 </v-col>
                 <v-col cols="12" md="4">
-                  <v-text-field
+                  <v-phone-input
                     v-model="newInterest['Phone Number']"
                     label="Phone Number"
                     variant="outlined"
                     density="comfortable"
-                    prepend-inner-icon="mdi-phone"
-                  ></v-text-field>
+                    country="US"
+                    :preferred-countries="['US', 'FR', 'ES', 'PT', 'GB']"
+                    :enable-searching-country="true"
+                  />
                 </v-col>
                 <v-col cols="12" md="4">
                   <v-text-field

components/InterestDetailsModal.vue

@@ -184,13 +184,15 @@
                   ></v-text-field>
                 </v-col>
                 <v-col cols="12" md="4">
-                  <v-text-field
+                  <v-phone-input
                     v-model="interest['Phone Number']"
                     label="Phone Number"
                     variant="outlined"
                     density="comfortable"
-                    prepend-inner-icon="mdi-phone"
-                  ></v-text-field>
+                    country="US"
+                    :preferred-countries="['US', 'FR', 'ES', 'PT', 'GB']"
+                    :enable-searching-country="true"
+                  />
                 </v-col>
                 <v-col cols="12" md="4">
                   <v-text-field