개선: 모바일 레이아웃 여백과 네비게이션 전환 보강

frontend/src/views/TierEditorView.vue

@@ -102,6 +102,12 @@ const isNewTierList = computed(() => tierListId.value === 'new')
 const isOwnTierList = computed(() => !!auth.user && !!ownerId.value && ownerId.value === auth.user.id)
 const canEdit = computed(() => !!auth.user && !previewMode.value && (!ownerId.value || ownerId.value === auth.user.id))
 const iconSizeOptions = [48, 64, 80, 96, 112]
+const touchSortableOptions = {
+  delayOnTouchOnly: true,
+  delay: 180,
+  touchStartThreshold: 8,
+  fallbackTolerance: 8,
+}
 const hasCustomTitle = computed(() => !!(title.value || '').trim())
 const fallbackTimestamp = computed(() => (updatedAt.value ? updatedAt.value : Date.now()))
 const effectiveAuthorName = computed(() => {
@@ -547,6 +553,7 @@ async function initSortables() {
   destroySortables()
 
   groupSortable.value = Sortable.create(groupListEl.value, {
+    ...touchSortableOptions,
     animation: 160,
     handle: '[data-group-handle]',
     ghostClass: 'ghost',
@@ -560,6 +567,7 @@ async function initSortables() {
   })
 
   poolSortable.value = Sortable.create(poolEl.value, {
+    ...touchSortableOptions,
     group: 'tier-items',
     animation: 160,
     draggable: '[data-item-id]',
@@ -577,6 +585,7 @@ async function initSortables() {
 
   dropSortables.value = Object.entries(groupDropEls.value).map(([, el]) =>
     Sortable.create(el, {
+      ...touchSortableOptions,
       group: 'tier-items',
       animation: 160,
       draggable: '[data-item-id]',