fix(frontend): standardize server time display

app/game-frontend/src/views/MainView.vue

@@ -1,4 +1,5 @@
 <script setup lang="ts">
+import { formatServerDateTime } from '@sammo-ts/common';
 import { computed, onMounted, onUnmounted, ref, watch } from 'vue';
 import { storeToRefs } from 'pinia';
 import { useMediaQuery } from '@vueuse/core';
@@ -68,14 +69,8 @@ const nationColor = computed(() => nation.value?.color ?? '#000000');
 const voteActive = computed(() => Boolean(frontStatus.value?.latestVote));
 const formatRecord = (entry: { text: string; createdAt?: string | Date }, appendTime = false): string => {
     if (!appendTime || /\d{2}:\d{2}\s*$/u.test(entry.text)) return formatLog(entry.text);
-    const parsed = entry.createdAt ? new Date(entry.createdAt) : null;
-    if (!parsed || Number.isNaN(parsed.getTime())) return formatLog(entry.text);
-    const time = new Intl.DateTimeFormat('ko-KR', {
-        timeZone: 'Asia/Seoul',
-        hour: '2-digit',
-        minute: '2-digit',
-        hour12: false,
-    }).format(parsed);
+    const time = formatServerDateTime(entry.createdAt, { format: 'hourMinute', fallback: '' });
+    if (!time) return formatLog(entry.text);
     return formatLog(`${entry.text} ${time}`);
 };