When a player starts a level but doesn't finish and goes to a different level, boardSquares should also be saved to GameProgress and re-initialized with it's previous state when a player returns to that level.
Currently a player can begin a level, go to a different page, return to that level and it appears their pieces are still there but boardSquares has been reset so it won't know about the pieces already on the board from before.
When a player starts a level but doesn't finish and goes to a different level, boardSquares should also be saved to GameProgress and re-initialized with it's previous state when a player returns to that level.
Currently a player can begin a level, go to a different page, return to that level and it appears their pieces are still there but boardSquares has been reset so it won't know about the pieces already on the board from before.