test(coding-agent): updated job poll displacement tests to use TranscriptContainer

- Replaced manual Container stubs with TranscriptContainer instances in test fixtures.
- Updated test context initialization to utilize the actual container implementation for chat message tracking.

packages/coding-agent/test/job-poll-displacement.test.ts

@@ -14,12 +14,13 @@ import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "bun:
 import type { AgentMessage } from "@oh-my-pi/pi-agent-core";
 import { resetSettingsForTest, Settings } from "@oh-my-pi/pi-coding-agent/config/settings";
 import { ToolExecutionComponent } from "@oh-my-pi/pi-coding-agent/modes/components/tool-execution";
+import { TranscriptContainer } from "@oh-my-pi/pi-coding-agent/modes/components/transcript-container";
 import { EventController } from "@oh-my-pi/pi-coding-agent/modes/controllers/event-controller";
 import { initTheme } from "@oh-my-pi/pi-coding-agent/modes/theme/theme";
 import type { InteractiveModeContext } from "@oh-my-pi/pi-coding-agent/modes/types";
 import { UiHelpers } from "@oh-my-pi/pi-coding-agent/modes/utils/ui-helpers";
 import type { SessionContext } from "@oh-my-pi/pi-coding-agent/session/session-context";
-import { type Component, Container, type TUI } from "@oh-my-pi/pi-tui";
+import type { Component, TUI } from "@oh-my-pi/pi-tui";
 
 const uiStub = { requestRender() {} } as unknown as TUI;
 
@@ -158,7 +159,8 @@ describe("EventController displaces consecutive waiting polls", () => {
 	});
 
 	function createFixture() {
-		const children: Component[] = [];
+		const chatContainer = new TranscriptContainer();
+		const children = chatContainer.children;
 		const pendingTools = new Map();
 		const ctx = {
 			isInitialized: true,
@@ -168,16 +170,7 @@ describe("EventController displaces consecutive waiting polls", () => {
 			updateEditorTopBorder: vi.fn(),
 			toolOutputExpanded: false,
 			pendingTools,
-			chatContainer: {
-				children,
-				addChild: (component: Component) => {
-					children.push(component);
-				},
-				removeChild: (component: Component) => {
-					const index = children.indexOf(component);
-					if (index !== -1) children.splice(index, 1);
-				},
-			},
+			chatContainer,
 			session: { getToolByName: () => undefined },
 			showWarning: vi.fn(),
 			viewSession: { getToolByName: () => undefined },
@@ -412,7 +405,7 @@ describe("UiHelpers.renderSessionContext collapses repeated todo snapshots", ()
 	});
 
 	it("removes the earlier todo snapshot when an assistant message replays two todo calls", () => {
-		const chatContainer = new Container();
+		const chatContainer = new TranscriptContainer();
 		let helpers!: UiHelpers;
 		const ctx = {
 			chatContainer,
@@ -487,7 +480,7 @@ describe("UiHelpers.renderSessionContext collapses repeated todo snapshots", ()
 	});
 
 	it("hands the trailing todo snapshot to the controller during mid-turn rebuild", () => {
-		const chatContainer = new Container();
+		const chatContainer = new TranscriptContainer();
 		const inheritDisplaceableTodo = vi.fn();
 		let helpers!: UiHelpers;
 		const ctx = {