fix(kvytky): client-side tariff fallback when static build has no server

At Docker build time Next.js renders /kvytky statically before the server
starts, so getTariffs() gets empty array. KvytkyTicketsClient now fetches
/api/tickets/tariffs on mount when serverTariffs is empty.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/sections/KvytkyTicketsClient.tsx

@@ -1,7 +1,7 @@
 'use client'
 /* eslint-disable @next/next/no-img-element */
 
-import { useMemo, useState } from 'react'
+import { useEffect, useMemo, useState } from 'react'
 import { useCart } from '@/context/CartContext'
 import {
   CHIP_ICONS,
@@ -126,11 +126,20 @@ export function KvytkyTicketsClient({
   title = 'Локації та Атракціони',
   tabLabels = DEFAULT_TAB_LABELS,
 }: KvytkyTicketsClientProps) {
+  const [tariffs, setTariffs] = useState<Tariff[]>(serverTariffs)
+
+  useEffect(() => {
+    if (serverTariffs.length > 0) return
+    fetch('/api/tickets/tariffs')
+      .then((r) => r.json())
+      .then((d: { tariffs?: Tariff[] }) => {
+        if (d.tariffs && d.tariffs.length > 0) setTariffs(d.tariffs)
+      })
+      .catch(() => {})
+  }, [serverTariffs.length])
+
   // Combo tariffs have their own section
-  const singleTariffs = useMemo(
-    () => serverTariffs.filter((t) => t.categoryTag !== 'combo'),
-    [serverTariffs]
-  )
+  const singleTariffs = useMemo(() => tariffs.filter((t) => t.categoryTag !== 'combo'), [tariffs])
 
   const [activeTab, setActiveTab] = useState<TabId>('all')