Add relations export and remote full backup/restore.

Expose GET/POST /api/v1/export/ for server dumps and add import UI for relations (CSV/JSON) plus remote backup controls.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/import/ExportFormatRow.vue

@@ -5,7 +5,7 @@
       <select :id="inputId" :value="modelValue" class="form-control" @change="onChange">
         <option value="csv">CSV (.csv)</option>
         <option value="json">JSON (.json)</option>
-        <option value="vcf">vCard (.vcf)</option>
+        <option v-if="variant === 'contacts'" value="vcf">vCard (.vcf)</option>
       </select>
     </div>
     <button
@@ -20,26 +20,29 @@
   <div v-if="result" class="alert" :class="result.error ? 'alert-error' : 'alert-success'" style="margin-top:12px;">
     <span v-if="result.error">{{ result.error }}</span>
     <span v-else>
-      Экспортировано контактов: <strong>{{ result.count }}</strong>
+      Экспортировано {{ entityLabel }}: <strong>{{ result.count }}</strong>
       ({{ result.formatLabel }}).
     </span>
   </div>
 </template>
 
 <script setup>
-import { useId } from 'vue'
+import { computed, useId } from 'vue'
 
-defineProps({
+const props = defineProps({
   modelValue: { type: String, default: 'csv' },
   exporting: { type: Boolean, default: false },
   disabled: { type: Boolean, default: false },
   result: { type: Object, default: null },
   buttonLabel: { type: String, default: 'Экспортировать' },
+  variant: { type: String, default: 'contacts' },
 })
 
 const emit = defineEmits(['update:modelValue', 'export'])
 const inputId = useId()
 
+const entityLabel = computed(() => (props.variant === 'relations' ? 'связей' : 'контактов'))
+
 function onChange(event) {
   emit('update:modelValue', event.target.value)
 }