fix: match Today paper concept

frontend/src/App.vue

@@ -322,6 +322,8 @@ const activeName = computed(() => {
   return lists.value.find((item) => item.id === activeList.value)?.name || '收集箱'
 })
 const todayHabitProgress = computed(() => `${todayHabitCompleted.value} / ${todayHabitTotal.value}`)
+const todayTaskRemaining = computed(() => Math.max(0, todayTaskTotal.value - todayTaskCompleted.value))
+const todayHabitRemaining = computed(() => Math.max(0, todayHabitTotal.value - todayHabitCompleted.value))
 const progressWidth = (completed: number, total: number) => `${total > 0 ? Math.min(100, Math.round(completed / total * 100)) : 0}%`
 const todayTaskProgressPercent = computed(() => progressWidth(todayTaskCompleted.value, todayTaskTotal.value))
 const todayHabitProgressPercent = computed(() => progressWidth(todayHabitCompleted.value, todayHabitTotal.value))
@@ -1542,11 +1544,11 @@ onUnmounted(() => {
           <TodayEnvironmentStrip :environment="todayEnvironment" :loading="todayEnvironmentLoading" :failed="todayEnvironmentError" />
           <div class="today-board__progress" aria-label="今日任务与习惯进度">
             <button class="today-track today-task-track" type="button" aria-controls="today-tasks" @click="navigateTodaySection('tasks')">
-              <span class="today-track-head"><strong>任务 {{ todayTaskCompleted }} / {{ todayTaskTotal }}</strong></span>
+              <span class="today-track-head"><strong>任务 {{ todayTaskCompleted }} / {{ todayTaskTotal }}</strong><span>还有 {{ todayTaskRemaining }} 项</span></span>
               <span class="today-track-rail" role="progressbar" aria-label="今日任务进度" aria-valuemin="0" :aria-valuemax="todayTaskTotal" :aria-valuenow="todayTaskCompleted"><i class="today-track-fill" :style="{ width: todayTaskProgressPercent }" /></span>
             </button>
             <button class="today-track today-habit-track" type="button" aria-controls="today-habits" @click="navigateTodaySection('habits')">
-              <span class="today-track-head"><strong>习惯 {{ todayHabitProgress }}</strong></span>
+              <span class="today-track-head"><strong>习惯 {{ todayHabitProgress }}</strong><span>还有 {{ todayHabitRemaining }} 项</span></span>
               <span class="today-track-rail" role="progressbar" aria-label="今日习惯进度" aria-valuemin="0" :aria-valuemax="todayHabitTotal" :aria-valuenow="todayHabitCompleted"><i class="today-track-fill" :style="{ width: todayHabitProgressPercent }" /></span>
             </button>
           </div>