feat(speaking): add StudentGrid.vue (4-col student cards)

src/views/Student/components/SpeakingClassPanel/StudentGrid.vue

@@ -0,0 +1,98 @@
+<template>
+  <div class="grid-4">
+    <div
+      v-for="s in students"
+      :key="s.userId"
+      class="student-card"
+      :class="['status-' + s.status]"
+      @click="$emit('click', s)"
+    >
+      <div class="avatar" :class="'avatar-' + s.status">
+        {{ s.name.charAt(0) }}
+      </div>
+      <span class="name">{{ s.name }}</span>
+      <span v-if="s.status === 'submitted'" class="indicator check">✓</span>
+      <span v-else-if="s.status === 'unsubmitted'" class="indicator dot pulse" />
+      <span v-else class="indicator dash">—</span>
+    </div>
+  </div>
+</template>
+
+<script lang="ts" setup>
+import type { ClassStudentSummary } from './types'
+
+defineProps<{ students: ClassStudentSummary[] }>()
+defineEmits<{ click: [student: ClassStudentSummary] }>()
+</script>
+
+<style lang="scss" scoped>
+.grid-4 {
+  display: grid;
+  grid-template-columns: repeat(4, minmax(0, 1fr));
+  gap: 12px;
+}
+
+.student-card {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  padding: 8px 12px;
+  border-radius: 8px;
+  cursor: pointer;
+  transition: box-shadow .15s ease;
+  background: #fff;
+  border: 2px solid transparent;
+
+  &:hover { box-shadow: 0 2px 8px rgba(0,0,0,.08); }
+
+  &.status-submitted   { border-color: #facc15; }
+  &.status-unsubmitted { border-color: #fde68a; }
+  &.status-not_started {
+    background: #f3f4f6;
+    border: 2px dashed #9ca3af;
+  }
+}
+
+.avatar {
+  flex-shrink: 0;
+  width: 32px; height: 32px;
+  border-radius: 50%;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 12px;
+  font-weight: 600;
+}
+.avatar-submitted   { background: #facc15; color: #111827; }
+.avatar-unsubmitted { background: #fef3c7; color: #92400e; }
+.avatar-not_started { background: #e5e7eb; color: #6b7280; }
+
+.name {
+  flex: 1;
+  font-size: 14px;
+  font-weight: 500;
+  color: #111827;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+.status-not_started .name { color: #9ca3af; }
+
+.indicator {
+  flex-shrink: 0;
+  font-size: 12px;
+}
+.indicator.check { color: #ca8a04; font-weight: 600; }
+.indicator.dash  { color: #9ca3af; }
+
+.indicator.dot.pulse {
+  width: 8px; height: 8px;
+  border-radius: 50%;
+  background: #fbbf24;
+  animation: pulse 1.5s ease-in-out infinite;
+}
+@keyframes pulse {
+  0%, 100% { opacity: 1; }
+  50%      { opacity: .4; }
+}
+</style>