App crashes when Windows Defender Ransomware Protection blocks cache directory creation

[Souipi]

Bug Description

When Windows Defender's Ransomware Protection (Controlled Folder Access) is enabled, it blocks Musly from creating theart_cache directory at C:\Users<user>\Documents\art_cache. When clicking "Connect" with valid credentials, the UI simply resets all fields without any feedback — no error message, no login, nothing happens from the user's perspective.

Steps to Reproduce

1. Enable Windows Defender Ransomware Protection (Controlled Folder Access)
2. Do NOT whitelist Musly in the allowed apps
3. Launch Musly and enter valid Navidrome server credentials
4. Click "Connect"
5. All fields reset, no login occurs, no error is displayed

Expected Behavior

The app should handle the file system permission error gracefully and either:

• Fall back to an in-memory cache
• Display an error message asking the user to whitelist the app or change the cache directory
• Continue the login flow without the art cache

App Version

v1.0.8

Subsonic Server

Navidrome (latest, Docker)

Relevant Logs

Navidrome logs (server-side authentication succeeds normally):
time="2026-03-29T10:00:45Z" level=info msg="Registering new player" client=Musly id=dM0WFv47qFvb3Fo940DF5F
requestId=15ebd3b61a6b/SrgkEIOqDY-000027 type=Dart username=test

Windows Defender Event Log (the actual blocker):
C:\Users\<user>\Desktop\Musly\musly.exe has been blocked from modifying
%userprofile%\Documents\art_cache by Controlled Folder Access.
Detection time: 2026-03-29T10:03:28.364Z
Process Name: C:\Users\<user>\Desktop\Musly\musly.exe
Path: %userprofile%\Documents\art_cache