What is the ruling on a wet dream (ihtilam) when no clear and tangible wetness is seen, but rather a drop clinging to the penis or a very small drop on the clothing? Is it considered maniyy (spermatic fluid) or madhiy (pre-seminal fluid)?

If you are certain that it is semen, you must perform ghusl (ritual bath), and you are not required to wash what has stained your clothes, due to the preponderant opinion of the purity of semen. If you are predominantly certain of one of the two possibilities, you act upon it. If you are in doubt, you apply the ruling of madhy (pre-seminal fluid) (purifying clothes and performing wudu') and the ruling of semen (performing ghusl).

If you wake up and find wetness: - If you are certain it is semen: Ghusl is obligatory, and semen is pure. Semen is recognized by its odor. - If you are certain it is not semen: Only purify what it stained, because it is impure. - If the matter is ambiguous and there was a preceding cause: Purify what it stained, due to the preponderant likelihood of it being madhy. - If the matter is ambiguous and there was no preceding cause: Perform ghusl, wudu', and purify what it stained as a precaution.