## Summary
Adds Playwright E2E tests for the SignIn dialog component and its
sub-forms.
## Tests added
- Dialog opens from login button in topbar
- Sign In form is the default view with email/password fields
- Toggle between Sign In and Sign Up forms
- API Key form navigation (forward and back)
- Terms of Service and Privacy Policy links present
- Form field presence verification
- Dialog close behavior (close button and Escape key)
- Forgot password link presence
- 'Or continue with' divider and API key button
## Notes
- Tests focus on UI navigation and element presence (no real Firebase
auth in test env)
- Dialog opened via `extensionManager.dialog.showSignInDialog()` API
- All selectors use stable IDs from the component source
(`#comfy-org-sign-in-email`, etc.)
## Task
Part of Test Coverage Q2 Overhaul (DLG-04).
## Conventions
- Uses Vue nodes with new menu enabled (`Comfy.UseNewMenu: 'Top'`)
- Tests read as user stories
- No full-page screenshots
- Proper waits, no sleeps
┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10587-test-add-SignIn-dialog-E2E-tests-DLG-04-3306d73d3650815db171f8c5228e2cf3)
by [Unito](https://www.unito.io)
---------
Co-authored-by: GitHub Action <action@github.com>
