Add 3 homepage scan e2e tests covering all roaster/roast match
permutations (new+new, existing+new, existing+existing). Fix
StaleElementReference in checkin test by using JS clicks for
Datastar-managed DOM elements.
Cover the check-in flow where neither the cafe nor the roast exist
beforehand. The test searches for a cafe via location search (mocked
Foursquare), scans a coffee bag via text prompt (mocked OpenRouter),
and submits the check-in. Adds spawn_app_with_all_mocks helper.
Roaster creation (basic + all fields), full brew chain through browser,
entity deletion with confirm dialog, AI extraction via text prompt with
mocked OpenRouter, and check-in wizard with saved cafe + existing roast.
