[Misdetection] DOCX file misdetected as spreadsheetml (XLSX) or application/zip

**What should the file have been detected as? What has the file been misdetected as?**
Valid .docx files are being misdetected as application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (XLSX) or application/zip instead of application/vnd.openxmlformats-officedocument.wordprocessingml.document (DOCX).

**Please link or attach the misdetected file below** (Do NOT upload PII!)

[test.docx](https://github.com/user-attachments/files/26089437/test.docx)

**Additional context**
DOCX, XLSX and PPTX share the same OOXML/ZIP container structure, which likely causes the confusion. A similar issue was reported for .ai files detected as PDF (#336).

Start by reproducing detection with the attached test.docx and compare the reported type with the expected DOCX MIME type. Read the handling of OOXML/ZIP containers and the related issue #336; done means valid DOCX files are no longer classified as XLSX or application/zip.

Written by the indexing model from the issue text.