feat: 跨实例同步移植第8轮（前端 helpers + 同步设置 UI）

新增同步 helpers（synced-options / synced-packs / game-options），在 instance helper 中补充同步类型与 API。新增实例设置「同步」标签页（SyncSettings）及 SyncSource / SyncedPacks / servers / command-history 四个弹窗，并把 CheckCircleButton、TeleportOverflowMenu 从 ui 包导出。同步相关的 en-US / zh-CN 文案已补齐（各 62 条）。game-settings-modal 留待下一轮。

apps/app-frontend/src/components/ui/modal/InstanceSettingsModal.vue

@@ -7,6 +7,7 @@ import {
 	FileArchiveIcon,
 	InfoIcon,
 	MonitorIcon,
+	RefreshCwIcon,
 	WrenchIcon,
 } from '@modrinth/assets'
 import {
@@ -23,6 +24,7 @@ import { computed, nextTick, ref, watch } from 'vue'
 import BackupSettings from '@/components/ui/instance_settings/BackupSettings.vue'
 import CoreComponentsSettings from '@/components/ui/instance_settings/CoreComponentsSettings.vue'
 import GeneralSettings from '@/components/ui/instance_settings/GeneralSettings.vue'
+import SyncSettings from '@/components/ui/instance_settings/SyncSettings.vue'
 import HooksSettings from '@/components/ui/instance_settings/HooksSettings.vue'
 import InstallationSettings from '@/components/ui/instance_settings/InstallationSettings.vue'
 import JavaSettings from '@/components/ui/instance_settings/JavaSettings.vue'
@@ -147,6 +149,14 @@ const tabs = computed<TabbedModalTab[]>(() => [
 		icon: CodeIcon,
 		content: HooksSettings,
 	},
+	{
+		name: defineMessage({
+			id: 'instance.settings.tabs.sync',
+			defaultMessage: 'Sync',
+		}),
+		icon: RefreshCwIcon,
+		content: SyncSettings,
+	},
 ])
 
 function getSupportedModpackLoaders() {