fix(charts): preserve comparison types and draggable window headings

Keep current lines and historical scatter points in a dedicated comparison chart type. Expose floating headings and use idempotent placement so StrictMode no longer masks production overlap.

src/features/agent/answer-ui/answer-view-state.ts

@@ -31,7 +31,7 @@ export function normalizeAnswerNodeState(node: Node, input?: unknown): AnswerUiN
     const start = index(proposed[0], labels.length);
     const end = Math.max(start, index(proposed[1], labels.length, labels.length - 1));
     const hidden = indices(state.hidden, series.length);
-    const chart: AnswerChartState = { type: "Chart", view: ["line", "bar", "table"].includes(String(state.view)) ? state.view as AnswerChartState["view"] : node.props.chart_type as "line" | "bar",
+    const chart: AnswerChartState = { type: "Chart", view: ["line", "bar", "table"].includes(String(state.view)) ? state.view as AnswerChartState["view"] : node.props.chart_type === "bar" ? "bar" : "line",
       hidden: hidden.length < series.length ? hidden : [], range: [start, end], point: index(state.point, labels.length), inspecting: state.inspecting === true };
     const data = answerChartTableData(node, chart);
     const table = normalizeAnswerNodeState({ type: "Table", props: data, children: [] }, { ...record(state.table), type: "Table" }) as AnswerTableState;

src/features/agent/answer-ui/catalog.ts

@@ -64,7 +64,7 @@ export const answerUiCatalog = defineCatalog(schema, {
       props: z
         .object({
           title: shortText,
-          chart_type: z.enum(["line", "bar"]),
+          chart_type: z.enum(["line", "bar", "time_comparison"]),
           x_axis_name: z.string().max(128).optional(),
           y_axis_name: z.string().max(128).optional(),
           x_data: z.array(shortText).min(1).max(100),
@@ -82,7 +82,7 @@ export const answerUiCatalog = defineCatalog(schema, {
         })
         .strict(),
       description:
-        "展示查询或用户提供的真实数据；series 必须与 x_data 对齐。浏览者可切换图形与数据表。"
+        "展示真实数据。chart_type=line 为普通折线，bar 为柱状图，time_comparison 为当前曲线与历史散点的同期对比。同期对比的 x_data 为 UTC+8 的 HH:mm 或 HH:mm:ss 共享时刻槽，series.type 使用 line/scatter，每组 sample_times 与 data 等长，保留真实带时区日期，缺测均填 null；历史点放入对应时刻槽。浏览者可切换图形与数据表。"
     },
     Evidence: {
       props: z

src/features/agent/answer-ui/interactive-chart.tsx

@@ -16,7 +16,7 @@ import { AnswerInteractionContext } from "./answer-ui-interaction-context";
 
 export type AnswerChartProps = {
   title: string;
-  chart_type: "line" | "bar";
+  chart_type: "line" | "bar" | "time_comparison";
   x_data: string[];
   series: SafeChartSeries[];
   x_axis_name?: string;
@@ -100,7 +100,7 @@ export const InteractiveChart = memo(function InteractiveChartView(props: Answer
   const numberLabel = chartValueLabel;
   const option = (type: "line" | "bar") => {
     const horizontal = type === "bar" && horizontalBars;
-    const seriesType = (series: SafeChartSeries) => view === props.chart_type ? series.type ?? type : type;
+    const seriesType = (series: SafeChartSeries) => view === (props.chart_type === "bar" ? "bar" : "line") ? series.type ?? type : type;
     const includesBars = visible.some((series) => seriesType(series) === "bar");
     const categoryAxis = { type: "category", data: labels, boundaryGap: type === "bar",
       axisLabel: { fontSize: 11, color: "#64748b", hideOverlap: !horizontal, interval: horizontal ? 0 : "auto",

src/features/agent/presentation/command-schema.ts

@@ -15,7 +15,7 @@ export function createViewSchemas(zod: typeof z = z, publication = false) {
   const chartSchema = z
     .object({
       title: z.string().max(200),
-      chart_type: z.enum(["line", "bar"]),
+      chart_type: z.enum(["line", "bar", "time_comparison"]),
       x_axis_name: z.string().max(128).optional(),
       y_axis_name: z.string().max(128).optional(),
       x_data: z.array(z.string().max(128)).min(1).max(100),