Support case-sensitive renames on Windows Nextcloud desktop client

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## Feature request

**Which Nextcloud Version are you currently using:** (see administration page)

[Nextcloud Hub 25 Autumn](https://nextcloud.com/) (32.0.0)
Nextcloud Desktop 3.17.0

**Is your feature request related to a problem? Please describe.**
Yes. I store all my files in external folders on a NAS using an ext4 filesystem, which is case-sensitive. Some of the client computers accessing these files are Windows PCs, which treat filenames that differ only in case as identical.

When a user renames a file or folder and only changes the case (e.g., Photos → PHOTOS), the server handles it without issue. However, the Nextcloud desktop client on Windows detects a conflict and is unable to resolve it automatically.

Currently, the only workaround is to manually rename the file or folder by adding an extra character, let it sync, and then rename it again with the intended case. If the folder contains a large number of files, this process can take hours.

I believe this is similar to this bug report: Bug #3943

**Describe the solution you'd like**
I would like the Nextcloud Windows client to handle case-only renames automatically, without creating conflicts. Ideally, the client should recognize that a case-only change is a valid rename and synchronize it correctly, even on case-insensitive filesystems like Windows.

**Describe alternatives you've considered**
Manually renaming the file/folder by adding an extra character, syncing, and then renaming it again to the desired case. This works but is time-consuming and error-prone.

**Additional context**
This issue is specific to Windows clients accessing case-sensitive storage (e.g., ext4 NAS shares). Mac and Linux clients handle case-only renames correctly. Handling this in the client would improve workflow efficiency and prevent unnecessary conflict files.