What is the ruling on eating mangoes from a farm without the owner's permission, and what must be done to atone for that? Is it forbidden to use substances to accelerate the ripening of mangoes and then sell them, and am I sinful for helping the employer with that? What should I do if this work is my sole source of livelihood?

It is not permissible for a worker to eat from the farms where he works unless permitted by their owners or if custom dictates such allowance. Whoever eats what is forbidden to him must seek the owner's forgiveness; if he does not, he must return the value of what he ate. If it is difficult to reach the rightful owner or his heirs, the worker should donate the value of what he ate on their behalf. If he is unable to do so due to poverty, he should humbly supplicate to Allah to appease the owner on the Day of Judgment and frequently engage in seeking forgiveness and performing good deeds.

If he is unaware of the exact amount he owes, he should strive to estimate it to the best of his knowledge, ensuring he fulfills his obligation.

Regarding the second question, the determining factor for ruling on the addition of a specific substance is the proof of harm. If harm is proven, then its addition and working with it are not permissible. The proof of harm is to be referred to experts and specialists.