fix: don't require untitled chat edited files to be part of the workspace (microsoft#232172)

Author: joyceerhl

src/vs/workbench/contrib/chat/browser/chatEditing/chatEditingSession.ts

@@ -36,6 +36,7 @@ import { IChatWidgetService } from '../chat.js';
 import { ChatEditingMultiDiffSourceResolver } from './chatEditingService.js';
 import { ChatEditingModifiedFileEntry, IModifiedEntryTelemetryInfo, ISnapshotEntry } from './chatEditingModifiedFileEntry.js';
 import { ChatEditingTextModelContentProvider } from './chatEditingTextModelContentProviders.js';
+import { Schemas } from '../../../../../base/common/network.js';
 
 export class ChatEditingSession extends Disposable implements IChatEditingSession {
 	private readonly _state = observableValue<ChatEditingSessionState>(this, ChatEditingSessionState.Initial);
@@ -517,7 +518,7 @@ export class ChatEditingSession extends Disposable implements IChatEditingSessio
 			return;
 		}
 
-		if (!this._workspaceContextService.getWorkspaceFolder(resource) && !(await this._fileService.exists(resource))) {
+		if (resource.scheme !== Schemas.untitled && !this._workspaceContextService.getWorkspaceFolder(resource) && !(await this._fileService.exists(resource))) {
 			// if the file doesn't exist yet and is outside the workspace, prompt the user for a location to save it to
 			const saveLocation = await this._dialogService.showSaveDialog({ title: localize('chatEditing.fileSave', '{0} wants to create a file. Choose where it should be saved.', this._chatAgentService.getDefaultAgent(ChatAgentLocation.EditingSession)?.fullName ?? 'Chat') });
 			if (!saveLocation) {