feat: 列宽拖拽 + 筛选栏 + 截图导出 + UI优化

- 新增 v-column-resize 指令，11 张表格均支持拖拽调整列宽
- 工作计划/商机跟单/要客拜访新增筛选栏（客户经理 + 状态）
- 汇总栏 chip 可点击筛选，支持重置与计数
- 新增截图导出功能（dom-to-image-more，像素级文字渲染）
- 截图范围从标题开始，自动隐藏操作按钮，5px白边
- 截图时页面闪烁动画反馈
- 全局 CSS 完善（列宽手柄、截图模式、捕获动画）
- 仪表盘 UI 细节优化 + 亮灯表标签调整
- 登录页 UI 改进

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

frontend/src/views/desktop/ManagerWorkspace.vue

@@ -287,7 +287,7 @@ const notesByDate = computed(() => {
               </svg>
               {{ date }}
             </h4>
-            <el-table :data="items" stripe size="small">
+            <el-table :data="items" stripe size="small" v-column-resize>
               <el-table-column prop="customer_name" label="客户" width="130">
                 <template #default="{ row }"><el-link type="primary" :underline="false" @click="openEdit('visit', row)">{{ row.customer_name }}</el-link></template>
               </el-table-column>
@@ -320,7 +320,7 @@ const notesByDate = computed(() => {
               </svg>
               {{ date }}
             </h4>
-            <el-table :data="items" stripe size="small">
+            <el-table :data="items" stripe size="small" v-column-resize>
               <el-table-column prop="category" label="分类" width="100"><template #default="{ row }"><el-tag size="small">{{ row.category }}</el-tag></template></el-table-column>
               <el-table-column prop="content" label="工作内容" min-width="250" show-overflow-tooltip>
                 <template #default="{ row }"><el-link type="primary" :underline="false" @click="openEdit('note', row)">{{ row.content }}</el-link></template>
@@ -339,7 +339,7 @@ const notesByDate = computed(() => {
         <!-- ═══ 工作计划 ═══ -->
         <el-tab-pane label="工作计划" name="work_plans">
           <div style="margin-bottom:12px"><el-button type="primary" size="small" @click="openCreate('plan')">+ 新建计划</el-button></div>
-          <el-table :data="workPlans" stripe size="small">
+          <el-table :data="workPlans" stripe size="small" v-column-resize>
             <el-table-column prop="customer_name" label="客户" width="130">
               <template #default="{ row }"><el-link type="primary" :underline="false" @click="openEdit('plan', row)">{{ row.customer_name }}</el-link></template>
             </el-table-column>
@@ -371,7 +371,7 @@ const notesByDate = computed(() => {
         <!-- ═══ 小微商机 ═══ -->
         <el-tab-pane label="小微商机" name="mini_biz">
           <div style="margin-bottom:12px"><el-button type="primary" size="small" @click="openCreate('mini')">+ 新建商机</el-button></div>
-          <el-table :data="miniBusiness" stripe size="small">
+          <el-table :data="miniBusiness" stripe size="small" v-column-resize>
             <el-table-column prop="customer_name" label="客户" width="130">
               <template #default="{ row }"><el-link type="primary" :underline="false" @click="openEdit('mini', row)">{{ row.customer_name }}</el-link></template>
             </el-table-column>
@@ -405,7 +405,7 @@ const notesByDate = computed(() => {
         <!-- ═══ 要客拜访 ═══ -->
         <el-tab-pane label="要客拜访" name="key_visits">
           <div style="margin-bottom:12px"><el-button type="primary" size="small" @click="openCreate('key')">+ 新建要客拜访</el-button></div>
-          <el-table :data="keyVisits" stripe size="small">
+          <el-table :data="keyVisits" stripe size="small" v-column-resize>
             <el-table-column prop="customer_name" label="客户" width="130">
               <template #default="{ row }"><el-link type="primary" :underline="false" @click="openEdit('key', row)">{{ row.customer_name }}</el-link></template>
             </el-table-column>