Backend crashes when loading a fits-gz file

[loveluthien]

Describe the bug

Backend crashes when loading a fits-gz file created by PhoSim which is a Photon Simulator producing mock sky images. There is no problem if we unzip it first and open it. Some error messages in the console point to the WebSocketExtension.h (see screenshot).

To Reproduce
Steps to reproduce the behavior:

1. open the fits-gz image
2. backend crashes

Expected behavior
No backend crashes.

Screenshots or videos
The error message from the console.

Platform info (please complete the following information):

• OS [e.g. macOS Monterey]: MacOS 14.4
• Browser [e.g. chrome, safari, electron app]: safari, chrome, and electron app
• Browser version [e.g. 22]:
• Backend branch [e.g. dev, v3b2 release]: dev
• Frontend branch [e.g. dev, v3b2 release]: dev

Additional context
The ftis-gz image can be opened by DS9 without any problem.