feat: 历史周报+图片预览+照片管理+导入优化+用户合并

新增:
- 历史周报: Dashboard/周报详情支持周选择器翻看往周，归档只读
- 图片预览: 全屏大图(移动端+PC端)，点击遮罩关闭
- PC端照片管理: 编辑时可上传/删除照片
- 客户导入改为更新模式: 重名自动更新信息，显示操作明细
- 导入跳过原因: 旧周报导入也显示每条跳过原因

优化:
- 填报进度权限: 经理只看到自己，支局长/领导看全员
- 客户经理暖灰色hash标签列
- 用户去重合并(4组)，数据完整迁移
- CLAUDE.md 更新到最新状态

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

frontend/src/views/mobile/VisitForm.vue

@@ -34,6 +34,8 @@ const customers = ref<any[]>([])
 const managers = ref<any[]>([])
 const uploadedPhotos = ref<string[]>([])
 const photoPreviews = ref<string[]>([])
+const previewDialogVisible = ref(false)
+const previewImageUrl = ref('')
 const uploading = ref(false)
 const customerSearch = ref('')
 
@@ -136,6 +138,11 @@ function onTimeRangeChange(val: [string, string] | null) {
   form.value.time_range = val ? val.join('-') : ''
 }
 
+function previewPhoto(url: string) {
+  previewImageUrl.value = url
+  previewDialogVisible.value = true
+}
+
 function removePhoto(index: number) {
   if (index < photoPreviews.value.length) {
     URL.revokeObjectURL(photoPreviews.value[index])
@@ -301,7 +308,7 @@ async function handleDelete() {
         </template>
         <div class="photo-area">
           <div v-for="(key, idx) in uploadedPhotos" :key="key" class="photo-item">
-            <img :src="photoPreviews[idx]" class="photo-thumb" v-if="photoPreviews[idx]" />
+            <img :src="photoPreviews[idx]" class="photo-thumb" v-if="photoPreviews[idx]" @click.stop="previewPhoto(photoPreviews[idx])" />
             <span class="photo-label">照片{{ idx + 1 }}</span>
             <button type="button" class="photo-remove-btn" @click="removePhoto(idx)">
               <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
@@ -338,6 +345,14 @@ async function handleDelete() {
         </button>
       </div>
     </el-form>
+
+    <!-- Image Preview Dialog -->
+    <teleport to="body">
+      <div v-if="previewDialogVisible" class="image-preview-overlay" @click="previewDialogVisible = false">
+        <img :src="previewImageUrl" class="image-preview-full" @click.stop />
+        <button class="image-preview-close" @click="previewDialogVisible = false">✕</button>
+      </div>
+    </teleport>
   </div>
 </template>