Is a wife considered a servant or a captive to her husband, and is "marriage a form of enslavement" as stated in the Hadith: "Fear Allah concerning women, for they are indeed captives (awan) with you"?

No religion has honored, protected, and preserved the rights of women like Islam. The hadith "They are captives (awan) with you" is understood in the context of enjoining good treatment of women. The meaning of her being a "captive" or "bondwoman" is not an insult; rather, it is an affirmation of the command to treat her well due to her vulnerability and the transfer of her obedience to her husband. The service of a wife to her husband is a matter of scholarly disagreement, with the preponderant opinion being that it is obligatory according to what is customary. This does not mean it is an insult to her, as the relationship between spouses is a partnership in marital life.