feat: 移动端表单必填项标记红色 * 号 + 提交校验

- 客户单位/日期/纪要内容/计划拜访时间 标记 *
- 缺失必填项时 ElMessage.warning 提示
- CSS: .required-star { color: var(--vermilion); }

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

frontend/src/views/mobile/DailyNoteForm.vue

@@ -60,6 +60,7 @@ onMounted(async () => {
 })
 
 async function handleSubmit() {
+  if (!form.value.note_date) { ElMessage.warning('请选择日期'); return }
   if (!form.value.content.trim()) { ElMessage.warning('请输入纪要内容'); return }
   submitLoading.value = true
   try {
@@ -108,7 +109,7 @@ async function handleDelete() {
     <el-form label-position="top" class="editorial-form">
       <el-form-item>
         <template #label>
-          <span class="form-label">日期</span>
+          <span class="form-label">日期 <span class="required-star">*</span></span>
         </template>
         <el-date-picker v-model="form.note_date" type="date" style="width:100%" />
       </el-form-item>
@@ -158,7 +159,7 @@ async function handleDelete() {
 
       <el-form-item>
         <template #label>
-          <span class="form-label">工作内容 <span class="form-label-required">*</span></span>
+          <span class="form-label">工作内容 <span class="required-star">*</span></span>
         </template>
         <el-input v-model="form.content" type="textarea" :rows="5" placeholder="今天做了什么..." />
       </el-form-item>
@@ -288,4 +289,5 @@ async function handleDelete() {
   animation: spin 0.6s linear infinite;
 }
 @keyframes spin { to { transform: rotate(360deg); } }
+.required-star { color: var(--vermilion); font-weight: 700; }
 </style>