feat: 桌面端表单必填项标记 * + 提交校验

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

frontend/src/views/desktop/ManagerWorkspace.vue

@@ -475,7 +475,7 @@ const notesByDate = computed(() => {
     <!-- Create/Edit Dialog -->
     <el-dialog v-model="dialogVisible" :title="(dialogMode === 'create' ? '新建' : '编辑') + ' ' + typeLabel(dialogType)" width="520px">
       <el-form label-position="top" v-if="form">
-        <el-form-item v-if="['visit','plan','mini','key'].includes(dialogType)" label="客户单位">
+        <el-form-item v-if="['visit','plan','mini','key'].includes(dialogType)" label="客户单位 *">
           <el-select v-model="form.customer_id" filterable remote :remote-method="handleCustomerSearch" placeholder="搜索选择客户" style="width:100%">
             <el-option v-for="c in customers" :key="c.id" :label="c.name" :value="c.id" />
             <template #empty>
@@ -586,4 +586,5 @@ const notesByDate = computed(() => {
 .quick-create-btn { display: inline-flex; align-items: center; gap: 4px; background: none; border: 1px dashed var(--gold); padding: 6px 12px; color: var(--gold-dark); font-family: var(--font-body); font-size: 12px; cursor: pointer; transition: all 0.2s; }
 .quick-create-btn:hover { border-color: var(--vermilion); color: var(--vermilion); background: rgba(184,71,46,0.03); }
 .select-empty-create { padding: 8px 12px; text-align: center; }
+.required-star { color: var(--vermilion); font-weight: 700; }
 </style>