feat: 导入增强 + 客户合并 + 同伴自定义 + 性能优化

=== 导入系统全面增强 ===
- 5 Sheet 完整导入：拜访/计划/商机/要客/纪要
- 同访人智能解析：中英文逗号/顿号/分号 → 系统用户UUID + 外部人员TEXT
- 客户自动创建：Excel中不存在的客户自动入库
- 模糊名称匹配：去空格 + 包含关系纠错
- manager_id 修正：导入时用客户分配的经理（非Excel列/非导入人）
- 模板更新：Sheet5「客户经理」→「填报人」，同访人示例含逗号分隔

=== 客户合并功能 ===
- PUT 改名碰撞检测 → 409 + 合并预览
- GET merge-preview / POST merge 端点
- 事务级迁移：Visit/WorkPlan/MiniBusiness/KeyVisit/联系人/分配
- 去重逻辑：联系人(name+phone)、分配(manager+role)
- last_visit_date 取最大值

=== 拜访记录完善 ===
- visits 新增 companion_names TEXT[] 列
- 同访人支持自定义输入（外部人员），el-select allow-create
- 移动端 VisitForm + PC端 ManagerWorkspace 统一
- 周报「客户经理」→「相关人员」（创建人+同访人）
- 纪要「客户经理」→「填报人」
- 删除拜访后重新计算 customer.last_visit_date

=== 客户选择放开 ===
- 客户经理可看到全部客户（不再限自己分配的）
- 拜访时客户下拉返回全量

=== 前端性能优化 ===
- Element Plus 按需加载 (unplugin-vue-components + unplugin-element-plus)
- 周报照片URL并行请求 (Promise.all)
- onMounted 三路并行 (loadReport + dropdowns + AI)
- nginx Cache-Control: immutable for /assets/
- Google Fonts preconnect hints
- 图片上传前 Canvas 压缩 (max 1920px, quality 0.8)

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

frontend/src/views/mobile/VisitForm.vue

@@ -6,6 +6,7 @@ import { todayStr } from '@/utils'
 import { visitsApi } from '@/api/visits'
 import { customersApi } from '@/api/customers'
 import { uploadApi } from '@/api/upload'
+import { compressImage } from '@/utils/image'
 import { useAuthStore } from '@/stores/auth'
 import ImagePreview from '@/components/ImagePreview.vue'
 import EditLogPanel from '@/components/EditLogPanel.vue'
@@ -121,8 +122,10 @@ async function handlePhotoUpload(event: Event) {
     const previewUrl = URL.createObjectURL(file)
     photoPreviews.value.push(previewUrl)
     try {
-      const res = await uploadApi.getPresignedUrl(file.name, file.type || 'image/jpeg')
-      await uploadApi.uploadFile(res.data.upload_url, file)
+      // Compress before upload to reduce storage & transfer
+      const compressed = await compressImage(file, { maxPixels: 1920, quality: 0.8 })
+      const res = await uploadApi.getPresignedUrl(compressed.name, compressed.type || 'image/jpeg')
+      await uploadApi.uploadFile(res.data.upload_url, compressed)
       uploadedPhotos.value.push(res.data.object_key)
       form.value.photos = [...uploadedPhotos.value]
     } catch (e: any) {
@@ -154,15 +157,28 @@ function removePhoto(index: number) {
   form.value.photos = [...uploadedPhotos.value]
 }
 
+function splitCompanions(values: string[]) {
+  // UUIDs → companions (system users), non-UUID strings → companion_names (external)
+  const uuidRe = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i
+  const sys: string[] = []; const ext: string[] = []
+  for (const v of values) {
+    if (uuidRe.test(v)) sys.push(v)
+    else if (v.trim()) ext.push(v.trim())
+  }
+  return { companions: sys, companion_names: ext }
+}
+
 async function handleSubmit() {
   if (!form.value.customer_id) { ElMessage.warning('请选择客户'); return }
   submitLoading.value = true
   try {
+    const { companions, companion_names } = splitCompanions(form.value.companions || [])
+    const body = { ...form.value, companions, companion_names }
     if (isEdit.value) {
-      await visitsApi.update(route.params.id as string, form.value)
+      await visitsApi.update(route.params.id as string, body)
       ElMessage.success('记录已更新')
     } else {
-      await visitsApi.create(form.value)
+      await visitsApi.create(body)
       ElMessage.success('拜访记录已提交')
     }
     router.push('/m')
@@ -269,9 +285,9 @@ async function handleDelete() {
 
       <el-form-item>
         <template #label>
-          <span class="form-label">同访人员</span>
+          <span class="form-label">同访人员 <span class="form-label-hint">可输入外部人员</span></span>
         </template>
-        <el-select v-model="form.companions" multiple filterable placeholder="选择同访人员" style="width:100%">
+        <el-select v-model="form.companions" multiple filterable allow-create default-first-option placeholder="选择或输入姓名（可多选）" style="width:100%">
           <el-option v-for="m in managers" :key="m.id" :label="m.name" :value="m.id" :disabled="m.id === auth.userId" />
         </el-select>
       </el-form-item>