Add local-first SPA architecture and containerized production deploy.

Move data access to use-cases and IndexedDB repositories with optional
remote fallback, changelog/sync ports, and encrypted local backup.
Add production Docker Compose (nginx frontend + optional backend) and
Apache host proxy configuration for deployment.

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

frontend/src/views/ContactDetailView.vue

@@ -160,17 +160,17 @@ const newRel = ref({
   interaction_intensity: 'intense',
 })
 
-const contactId = computed(() => Number(route.params.id))
+const contactId = computed(() => route.params.id)
 
 const contactRelations = computed(() =>
   store.relations.filter(
-    (r) => r.source === contactId.value || r.target === contactId.value
+    (r) => String(r.source) === String(contactId.value) || String(r.target) === String(contactId.value)
   )
 )
 
 const otherContacts = computed(() =>
   store.contacts
-    .filter((c) => c.id !== contactId.value)
+    .filter((c) => String(c.id) !== String(contactId.value))
     .slice()
     .sort((a, b) => a.name.localeCompare(b.name, 'ru'))
 )