feat(workbench): group live presentation steps into expandable categories

Group adjacent live display steps into category menus with merged snapshots, original-step submenus and scoped playback.

The submenu exposes the latest raw step, so explicit selections must remain pinned. Locate failed and cancelled steps using the full group sequence, and prevent an exiting menu from dismissing a trigger-owned reopen. Regression tests reproduce these paths before the fixes.

Validation: lint, typecheck, 1178 unit tests and 10 focused browser cases passed; update the presentation history guide.

tests/browser/investigation-chart-windows.e2e.ts

@@ -1,5 +1,5 @@
 import { expect, test, type Page } from "@playwright/test";
-import { investigationFixture, mockInvestigationPresentation, selectInvestigation } from "./support/mock-investigation-presentation";
+import { investigationFixture, mockInvestigationPresentation, selectInvestigation, showInvestigationMap } from "./support/mock-investigation-presentation";
 
 const chart = (index: number) => ({
   action: "open_chart", chart_id: "pressure", evidence_refs: ["synthetic:pressure"],
@@ -260,6 +260,7 @@ test("playback restores charts without opening windows while live results remain
     run_id: task.active_run!.run_id, execution_generation: 1, occurred_at: task.created_at, command }));
   const mock = await mockInvestigationPresentation(page, [task], saved);
   await selectInvestigation(page, task.title);
+  await showInvestigationMap(page);
   const panel = page.getByLabel("调查实时展示", { exact: true });
   await expect(panel.getByRole("button", { name: "播放历史", exact: true })).toBeVisible();
   await expect(page.locator("[data-floating-window]")).toHaveCount(0);
@@ -276,7 +277,7 @@ test("playback restores charts without opening windows while live results remain
   const progress = panel.getByRole("slider", { name: "历史播放进度" });
   await progress.focus();
   await page.keyboard.press("ArrowRight");
-  await expect(panel.getByRole("combobox", { name: "切换展示动作" })).toContainText("2.");
+  await expect(panel.getByRole("button", { name: "切换展示动作" })).toHaveText("地图操作");
   await expect(page.locator("[data-floating-window]")).toHaveCount(0);
   await page.keyboard.press("ArrowRight");
   await expect(page.locator("[data-floating-window]")).toHaveCount(0);