Set up cucumber

[kantord]

this sets up "end to end" testing for the project:

• sets up a runner to run playwright tests written as feature files
• adds a very convenient way to use ARIA-role based steps, plus a way to remap "ugly" ARIA roles, such as being able to write "list item" instead of "listitem" for a more natural-sounding English
• adds a simple helper for authentication: log in once and recycle cookies across different tests to avoid redundancy in E2E tests to keep them fast

gotchas:

• does not actually target a real BE yet, since that is not yet configured. it should be pretty easy to do it using testcontainers even being able to use different scenarios with different containers. but since BE won't return any interesting data yet this is pointless
• i avoided writing any tests targeting MSW data because that would not be very useful, but this is 100% possible to do if it's needed for whatever reason

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