fix(cost): 修复图表全屏显示和默认选择问题

- 添加默认选择所有图表项的逻辑
- 修复全屏图表对话框的高度设置
- 调整全屏图表的布局结构为flex布局
- 优化图表头部和主体的样式设置

klp-ui/src/views/cost/comprehensive.vue

@@ -1321,6 +1321,8 @@ export default {
         }
       } catch (e) { /* ignore */ }
       this.chartSelectedKeys = selected
+      // default: select all
+      if (!this.chartSelectedKeys.length) this.chartSelectedKeys = [...allKeys]
     },
     saveChartSelection() {
       if (!this.activeReport) return
@@ -1440,9 +1442,9 @@ export default {
 /deep/ .summary-row td .cell { color: #303133; }
 .summary-label { font-weight: bold; color: #303133; padding: 0 5px; }
 .summary-val { font-weight: bold; color: #303133; }
-/deep/ .chart-fullscreen { width: 100% !important; max-width: 100% !important; margin: 0 !important; }
-/deep/ .chart-fullscreen .el-dialog__body { max-height: calc(100vh - 90px); overflow: auto; padding: 16px 20px; }
-/deep/ .chart-fullscreen .el-dialog__header { padding: 12px 20px; }
+/deep/ .chart-fullscreen { width: 100% !important; max-width: 100% !important; height: 100vh !important; margin: 0 !important; display: flex; flex-direction: column; }
+/deep/ .chart-fullscreen .el-dialog__body { flex: 1; max-height: none; overflow: auto; padding: 16px 20px; }
+/deep/ .chart-fullscreen .el-dialog__header { padding: 12px 20px; flex-shrink: 0; }
 .chart-tag-bar { padding: 0 4px 8px; }
 .chart-tag-row { display: flex; flex-wrap: wrap; align-items: center; margin-bottom: 4px; }
 .chart-tag-row:last-child { margin-bottom: 0; }