Harden the suite: cross-browser CI, parallel runs, typed data, selector + flake fixes

[larelgit]

Changes
- ci: cross-browser matrix (chromium/firefox/webkit), parallel -n 4,
runs on every push and pull request
- fix(cart): Proceed-To-Checkout is an with no href → no ARIA link role.
Switched to the stable a.check_out class (also survives i18n)
- fix(ci): expose base_url fixture so xdist workers can navigate
(pytest-base-url doesn't propagate the ini value to -n workers); block the
fundingchoices consent overlay that intercepted clicks
- refactor: typed test data with TypedDict (User, PaymentCard), propagated
through page-object signatures so pyright catches bad fields before the form
- refactor(tests): extract register_via_ui flow, kill duplicate signup steps
- build: pin dependency versions for reproducible CI
- test: stop hardcoding --browser in pytest.ini so the CLI override works
- docs/chore: README + .gitignore

Verification
- pyright: 0 errors, 0 warnings
- chromium: 12 passed (-n 4 --reruns 2)
- firefox: 12 passed (-n 4 --reruns 2)

[Copilot]

Pull request overview

This PR hardens the Playwright+pytest E2E suite for more deterministic, scalable CI execution by adding cross-browser coverage, parallelism support, and stronger typing around generated test data and page-object APIs.

Changes:

• Add cross-browser GitHub Actions matrix (chromium/firefox/webkit) and run the suite in parallel via pytest-xdist.
• Introduce typed test data (TypedDict) for users and payment cards, and propagate types through tests and page objects.
• Refactor repeated signup steps into a reusable register_via_ui flow; improve selector stability and update docs/config accordingly.

Reviewed changes

Copilot reviewed 11 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
utils/data_generator.py	Adds TypedDict-based shapes for generated user and payment card data.
tests/test_checkout.py	Uses typed User fixture and the shared register_via_ui flow for the purchase journey.
tests/test_auth.py	Refactors signup test to use shared flow; annotates fixtures as User.
requirements.txt	Pins Python test dependencies and adds pytest-xdist for parallel execution.
README.md	Updates stack + local run instructions for cross-browser and parallel runs.
pytest.ini	Removes hardcoded --browser so CLI/CI matrix can override.
pages/signup_page.py	Types fill_account_details to accept User.
pages/flows.py	Adds shared cross-page register_via_ui flow to deduplicate tests.
pages/checkout_page.py	Types payment flow input as PaymentCard.
pages/cart_page.py	Switches checkout selector to stable CSS class (a.check_out).
conftest.py	Exposes base_url for xdist workers; expands ad/consent host blocking; types helper signature.
.gitignore	Tweaks ignored artifacts and virtualenv entries.
.github/workflows/tests.yml	Runs suite on push/PR via cross-browser matrix; installs target browser and runs -n 4.

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[Copilot]

Pull request overview

Copilot reviewed 12 out of 14 changed files in this pull request and generated no new comments.