What is the evidence from the Qur'an and Sunnah that writing a divorce without intention does not constitute a divorce, and that it is considered a form of metaphorical expression (kinayah) by which divorce does not occur unless intended?

The jurists mentioned a proof and a reasoning for this issue. As for the proof, it is the Hadith of Umar ibn al-Khattab, may Allah be pleased with him: "Deeds are only by intentions." As for the reasoning, it is because writing is susceptible to other purposes such as "testing the pen, improving handwriting, and grieving the family, without intention." Since it can have multiple purposes, it is necessary to refer to the intention.