Implement a way of creating UI tests

The actual need at hand is to be able to "e2e" or integration test the full game to catch otherwise hard to spot bugs with our currently low unit test coverage. I kinda don't want to play even our short example game manually over and over.

UI tests should run the game and be able to click on UI and be able to figure out if the expected thing happened.

UI tests should not assert implementation details not visible to the player in the UI.

Unknowns:

• How does for example Playwright deal with HTML5 canvas elements? In the browser the DOM simply has canvas elements and the actual UI is inside those
• for manual debugging, there is https://github.com/konvajs/konva-devtool to peek behind the ... canvas curtain
• Does konva provide some UI testing solution for applications? The konva doc speaks of unit tests and TDD and while that's great - without sarcasm! - for the framework development, I'd for one really like to have a way of "e2e testing" the game with UI tests
• Would UI tests even be the best way for e2e/integration testing

No files, tests, or entry points are named. Start by evaluating how the game’s HTML5 canvas and Konva UI can be exercised with Playwright or another approach, using the short example game as the test target. Done means there is a chosen approach that can run the game, click player-visible UI, and verify expected outcomes without asserting implementation details.