What is the original Mandarin translation for this proverb: "The wise man and the tortoise travel but never leave their home."
“The wise man and the tortoise travel but never leave their home

There's no such proverb in Chinese.
The only one remotely similar to this 'proverb' in Chinese is 秀才不出門，能知天下事 (A talented person can know the world without going out)
I suspect whoever coined this 'proverb', heard it somewhere that there's a Chinese idiom expressing &quot;a wise man doesn't need to leave home&quot; and tried to be creative, made up a proverb comparing a wise man to a tortoise because both of them don't need to leave home.
The author missed the fact that it is 'a wise man doesn't need to leave home', not 'like a tortoise, a wise man doesn't leave his home'. A tortoise doesn't leave his home because he is carrying it at all times. The author didn't care a wise man doesn't carry his home with him, as long as they both don't leave home, they are comparable in his mind.
Another possible source of that 'proverb' maybe the Chinese idiom 運籌帷幄， 決勝千里 (strategizing in one's tent can win battles thousands of miles away). Which describes a wise commander who doesn't need to go outside to win a war.