Add rounds model

[mwickett]

Games -> Rounds -> Scores

This will make things more straightforward for stat generation (most rounds won, longest / shortest games, etc.)

[mwickett]

Couple of stages in here.

1. Add the rounds model to the DB, as optional for now (because of existing data) ✅
2. Refactor game logic out to its own file ✅
3. Break it apart into smaller functions ✅
4. Try to add some testing (see Get some Playwright tests started #55 )
5. Fix up handing the more than one player above 75 points issue
6. Refactor to use rounds
7. Ship it!

[mwickett]

Bug where the game doesn't show as complete after the first player has a winning score. Reproduced on main, so it's not the code change here I don't think.

After entering the score - here I can still add an additional score, which is invalid.

This is after a refresh 👇 so some kind of state issue