fix: refresh UI after checkpoint restore operation

- Added postStateToWebview() call after checkpoint deletion/restoration
- This ensures the webview displays the restored messages correctly
- Fixes issue where chat history disappeared visually after restore
- Updated tests to include the mock for postStateToWebview

Fixes #9307

src/core/webview/__tests__/checkpointRestoreHandler.spec.ts

@@ -48,6 +48,7 @@ describe("checkpointRestoreHandler", () => {
 		mockProvider = {
 			getCurrentTask: vi.fn(() => mockCline),
 			postMessageToWebview: vi.fn(),
+			postStateToWebview: vi.fn(), // Add this method to the mock
 			getTaskWithId: vi.fn(() => ({
 				historyItem: { id: "test-task-123", messages: mockCline.clineMessages },
 			})),

src/core/webview/checkpointRestoreHandler.ts

@@ -75,6 +75,9 @@ export async function handleCheckpointRestoreOperation(config: CheckpointRestore
 			// Get the updated history item and reinitialize
 			const { historyItem } = await provider.getTaskWithId(currentCline.taskId)
 			await provider.createTaskWithHistoryItem(historyItem)
+
+			// Update the webview to show the restored messages
+			await provider.postStateToWebview()
 		}
 		// For edit operations, the task cancellation in checkpointRestore
 		// will trigger reinitialization, which will process pendingEditAfterRestore