Group e2e tests (tldraw#7129)

Add some basic group e2e tests. There's a ton more we could add, but
went for the most basic ones for now as they do tend to be on the slow
side.

### Change type

- [x] `other`

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Adds end-to-end tests and fixtures for groups (CRUD, reorder, file
ops, sharing) with supporting test utilities and minor test-id/DO route
adjustments.
> 
> - **E2E Tests**:
> - Add `tests/groups.spec.ts` covering group create/rename/delete,
expand/collapse persistence, reordering via drag, file
create/move/drag/pin/unpin/duplicate/delete, move-to-home, and
sharing/invitation flows with cross-user propagation.
> - **Fixtures/Helpers**:
> - New `GroupInviteDialog` fixture; register in `tla-test.ts` and
`helpers.ts`.
> - Extend `Sidebar` fixture with group operations, file operations
within groups, drag-and-drop utilities, and invite-link copy methods;
add `createGroupButton` selector.
> - `Database` fixture: add `enableGroupsFrontend()` and simplify
cleanup to hit `prepare-for-test` without legacy header.
>   - Remove init-mode code from `HomePage`.
> - **App UI**:
> - Change sidebar create-group button test id to `tla-create-group` in
`TlaSidebar.tsx`.
> - **Sync Worker (test utilities)**:
> - Simplify `__test__prepareForTest`: always set `groups_backend`,
clear all user groups, and recreate home group; update
`/app/__test__/user/:userId/prepare-for-test` route accordingly.
> - **Cleanup**:
>   - Remove `run-both-modes.sh` and `init-mode-verification.spec.ts`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
18c142a. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: MitjaBezensek

apps/dotcom/client/e2e/fixtures/Database.ts

@@ -64,6 +64,31 @@ export class Database {
 		await sql`SELECT * FROM migrate_user_to_groups(${id}, ${inviteSecret})`.execute(db)
 	}
 
+	/**
+	 * Enable groups frontend flag for a user
+	 */
+	async enableGroupsFrontend(isOther: boolean = false): Promise<void> {
+		const id = await this.getUserId(isOther)
+		if (!id) throw new Error('User not found')
+
+		// Get current flags
+		const result = await sql<{
+			flags: string | null
+		}>`SELECT flags FROM public.user WHERE id = ${id}`.execute(db)
+
+		const currentFlags = result.rows[0]?.flags || ''
+		const flagsArray = currentFlags.split(/[,\s]+/).filter(Boolean)
+
+		// Add groups_frontend if not present
+		if (!flagsArray.includes('groups_frontend')) {
+			flagsArray.push('groups_frontend')
+		}
+
+		// Update with new flags
+		const newFlags = flagsArray.join(',')
+		await sql`UPDATE public.user SET flags = ${newFlags} WHERE id = ${id}`.execute(db)
+	}
+
 	private async cleanUpUser(isOther: boolean) {
 		const fileName = getStorageStateFileName(this.parallelIndex, isOther ? 'suppy' : 'huppy')
 		if (!fs.existsSync(fileName)) return
@@ -73,9 +98,6 @@ export class Database {
 			// eslint-disable-next-line no-restricted-globals
 			await fetch(`http://localhost:3000/api/app/__test__/user/${id}/prepare-for-test`, {
 				method: 'POST',
-				headers: {
-					'x-legacy': process.env.TLDRAW_INIT_MODE === 'new' ? 'false' : 'true',
-				},
 			})
 		} catch (e) {
 			console.error('Error', e)

apps/dotcom/client/e2e/fixtures/GroupInviteDialog.ts

@@ -0,0 +1,36 @@
+import type { Locator, Page } from '@playwright/test'
+import { expect, step } from './tla-test'
+
+export class GroupInviteDialog {
+	public readonly dialog: Locator
+	public readonly acceptButton: Locator
+	public readonly declineButton: Locator
+
+	constructor(public readonly page: Page) {
+		this.dialog = this.page.getByText("You've been invited to group")
+		this.acceptButton = this.page.getByRole('button', { name: 'Accept and join group' })
+		this.declineButton = this.page.getByRole('button', { name: 'No thanks' })
+	}
+
+	async isVisible() {
+		return this.dialog.isVisible()
+	}
+
+	async expectIsVisible() {
+		await expect(this.dialog).toBeVisible()
+	}
+
+	async expectIsNotVisible() {
+		await expect(this.dialog).not.toBeVisible()
+	}
+
+	@step
+	async acceptInvitation() {
+		await this.acceptButton.click()
+	}
+
+	@step
+	async declineInvitation() {
+		await this.declineButton.click()
+	}
+}

apps/dotcom/client/e2e/fixtures/HomePage.ts

@@ -16,18 +16,6 @@ export class HomePage {
 		this.signInButton = this.page.getByTestId('tla-sign-in-button')
 		this.tldrawEditor = this.page.getByTestId('tla-editor')
 		this.tldrawCanvas = this.page.getByTestId('canvas')
-
-		// Set localStorage flag based on environment variable
-		const initMode = process.env.TLDRAW_INIT_MODE || 'legacy'
-		this.page.addInitScript((mode) => {
-			if (mode === 'new') {
-				// eslint-disable-next-line no-restricted-syntax
-				localStorage.setItem('tldraw_groups_init', 'true')
-			} else {
-				// eslint-disable-next-line no-restricted-syntax
-				localStorage.removeItem('tldraw_groups_init')
-			}
-		}, initMode)
 	}
 
 	@step