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/App.vue

@@ -388,4 +388,82 @@ h1, h2, h3, h4, h5, h6 {
   cursor: pointer; border-radius: 50%; transition: background 0.2s;
 }
 .image-preview-close:hover { background: rgba(255,255,255,0.35); }
+
+/* ── Screenshot capture mode ── */
+.taking-screenshot { background: #fff !important; }
+.taking-screenshot * { background-color: transparent; }
+.taking-screenshot .el-card,
+.taking-screenshot .el-table,
+.taking-screenshot .el-table__header,
+.taking-screenshot .el-table__body,
+.taking-screenshot .filter-bar,
+.taking-screenshot .summary-bar,
+.taking-screenshot .page-head { background: #fff !important; }
+.taking-screenshot .screenshot-hide { display: none !important; }
+.taking-screenshot .el-table__fixed-right { display: none !important; }
+
+/* ── Screenshot capture animation ── */
+.body-capturing .work-plans-page,
+.body-capturing .mini-biz-page,
+.body-capturing .key-visits-page {
+  position: relative;
+}
+.body-capturing .work-plans-page::after,
+.body-capturing .mini-biz-page::after,
+.body-capturing .key-visits-page::after {
+  content: '';
+  position: fixed; inset: 0; z-index: 9998;
+  background: rgba(255,255,255,0.6);
+  pointer-events: none;
+  animation: capture-flash 0.35s ease-out;
+}
+@keyframes capture-flash {
+  0% { opacity: 0; }
+  50% { opacity: 1; }
+  100% { opacity: 0; }
+}
+
+/* ── Column resize handle ── */
+.el-table__header th {
+  position: relative !important;
+}
+/* Exclude gutter (scrollbar spacer) and selection column from resize */
+.el-table__header th.el-table__cell--selection .col-resize-handle,
+.el-table__header th.gutter .col-resize-handle {
+  display: none !important;
+}
+.col-resize-handle {
+  position: absolute;
+  right: 0;
+  top: 0;
+  bottom: 0;
+  width: 6px;
+  cursor: col-resize;
+  z-index: 1;
+  transition: background 0.15s;
+}
+.col-resize-handle::after {
+  content: '';
+  position: absolute;
+  right: 1px;
+  top: 20%;
+  bottom: 20%;
+  width: 2px;
+  border-radius: 1px;
+  background: transparent;
+  transition: background 0.15s;
+}
+.el-table__header th:hover .col-resize-handle::after,
+.col-resize-handle.is-resizing::after {
+  background: var(--gold);
+}
+.col-resize-handle:hover::after,
+.col-resize-handle.is-resizing::after {
+  background: var(--gold) !important;
+}
+/* Prevent text selection while resizing columns */
+body.col-resizing {
+  cursor: col-resize !important;
+  user-select: none !important;
+}
 </style>