[Feature]: Cookie Assertions in PageAssertions

[gamestheory]

🚀 Feature Request

Verifying cookies is essential for testing authentication and session states. Currently, developers must manually call page.context().cookies(), which does not support the auto-waiting convenience of the assertThat API.

Example

Proposed Methods: assertThat(page).hasCookie(String name), assertThat(page).hasCookieValue(String name, String value).

Motivation

API Consistency: Brings cookie verification into the same PageAssertions family as hasTitle() and hasURL().
Handling Asynchronicity: Automatically polls for the cookie to be set.

[yury-s]

The main value of Playwright web assertions is that they auto-retry. There is not much point in auto retrying cookies and the asserting a presence of a cookie can be wrapped in a helper method easily.