Improve engine play experience

[WandererXII]

https://lishogi.org/forum/lishogi-feedback/computer-always-plays-static-rook

To avoid deterministic behavior of the engine:

Maybe we could make the first engine move (sente or gote first move) be selected at random from a list of moves with weights and not send to the engine.
Sente maybe one of:

• P-76
• P-26
• P-56
• R-78
• ...

Gote should have a list of moves for the most common opening moves:
If sente 'P-76', gote would play one of:

• P-34
• P-84
• ...

If sente 'P-26', gote would play one of:

• P-84
• P-34
• ...

More than the first move is not something I think we should code here...

One problem might be people aborting games till they get the opening they want, but prob not a big issue.

Could maybe yaneuraou be instructed to play certain opening with an opening book? If so we could add another field to the "Play against computer" window and let the engine handle it.

[ddugovic]

In recent decades chess engines changed from supporting CECP (WinBoard/XBoard) to UCI, removing the responsibility of engines playing openings (the interface or some other script would play opening moves instead).

I'd be surprised if yaneuraou or other shogi engines natively supported opening books.

[IcefoxKishi]

The USI interface allows for usage of opening books like this one: https://yaneuraou.yaneu.com/2025/06/22/2-33m-book-released-for-free/

[WandererXII]

Added a small 'opening book' with valid moves for the engine to play. Currently only depth 2, but we could extend in some cases. Figured it's probably easier than handling opening books inside different engines...
Kind of a draft, so open to changes: https://github.com/WandererXII/lishogi/blob/master/modules/shoginet/src/main/OpeningBook.scala#L54