style(提交列表): 翻上一条下一条只用 ↑ ↓，去掉 ← →

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/oj/submission/components/FlowchartPane.vue

@@ -258,7 +258,7 @@ const canRetry = computed(
     </div>
 
     <div v-if="!narrow" class="foot">
-      <span class="keys"><kbd>↑</kbd><kbd>↓</kbd><kbd>←</kbd><kbd>→</kbd></span>
+      <span class="keys"><kbd>↑</kbd><kbd>↓</kbd></span>
       <span>换上一张 / 下一张</span>
       <div class="spacer"></div>
       <span v-if="position">本页第 {{ position.index }} / {{ position.count }} 条</span>

apps/web/src/oj/submission/components/SubmissionPane.vue

@@ -398,7 +398,7 @@ function openStandalone() {
     </template>
 
     <div v-if="!narrow" class="foot">
-      <span class="keys"><kbd>↑</kbd><kbd>↓</kbd><kbd>←</kbd><kbd>→</kbd></span>
+      <span class="keys"><kbd>↑</kbd><kbd>↓</kbd></span>
       <span>
         {{
           teacher

apps/web/src/oj/submission/list.vue

@@ -314,8 +314,8 @@ function move(step: 1 | -1) {
 
 const [todayPanel, toggleTodayPanel] = useToggle(false)
 
-// ← → 和 ↑ ↓ 一样（9 月加方向键时就是四个键都能翻，老师已经用惯了）
-onKeyStroke(["ArrowUp", "ArrowDown", "ArrowLeft", "ArrowRight"], (e: KeyboardEvent) => {
+// 只用 ↑ ↓（用户定的，← → 不要）
+onKeyStroke(["ArrowUp", "ArrowDown"], (e: KeyboardEvent) => {
   if (!isDesktop.value || todayPanel.value) return
   // 别的控件已经处理了这次按键（下拉框自己会开菜单、换选项）
   if (e.defaultPrevented) return
@@ -335,7 +335,7 @@ onKeyStroke(["ArrowUp", "ArrowDown", "ArrowLeft", "ArrowRight"], (e: KeyboardEve
   }
   if (!rows.value.length) return
   e.preventDefault()
-  move(e.key === "ArrowUp" || e.key === "ArrowLeft" ? -1 : 1)
+  move(e.key === "ArrowUp" ? -1 : 1)
 })
 
 // 手机上没有右栏：点一行从右边滑出整屏的详情