Implement king square highlights for end game states

[Bayuo321]

• Implement findKingSquare in util.ts to locate king position from FEN
• Ensure chessground reloads after game ends (ctrl.ts)
• Differentiate highlights based on mate, timeout, resign or draw/stalemate (ground.ts)
• Created new endgame state icons (public/images/icons)
• Add SCSS pulsing animation with the SVG icons on king squares for enhanced visuals (_chessground.scss)

Co-authored-by: Pedro Antunes [email protected]
@Piti06

[Bayuo321]

Here is a short video demonstrating the feature changes in action.

In addition to what's shown in the video, we've tested all other endgame scenarios including stalemate, opponent disconnected, etc and confirm that all are working as expected.

FeaturePreview.mp4

Here is a longer video comparing the old version with the new one - https://youtu.be/4s-OVVlAaMA

[kraktus]

Hey, thanks for the PR! I agree with the intention, but I don't think the flashing animation is the proper way to implement it, too distracting.

I'd rather have the information put like good/bad moves, etc

It'd also reduce maintenance cost.

[Piti06]

Hey, thanks for the PR! I agree with the intention, but I don't think the flashing animation is the proper way to implement it, too distracting.

I'd rather have the information put like good/bad moves, etc

It'd also reduce maintenance cost.

Hi!
Sorry if we missunderstood what you meant but our proposal is only related to when the game finishes.
We think that currently, Lichess provides limited visual feedback when a game ends. The interface displays a small result message and plays a subtle beep sound.
We've implemented those visual animations with means to enhance the user experience.
What do you think we should improve?
Thank you.

[kraktus]

Sorry if we missunderstood what you meant but our proposal is only related to when the game finishes.

I meant that the information should appear via a small information bubble like for good/bad moves. Not via a flashing square.

[Piti06]

Okay, we will work on that.

[SergioGlorias]

maybe can close #15385