Windows startup fails with Backend exited during startup readiness check: exit code: 3

[enderzcx]

On Windows, the app can fail to start with Backend exited during startup readiness check: exit code: 3.

In my case the real cause was a permission error on:
C:\Users\Administrator\.cache\nowledge-graph

The backend should fall back to a writable app-owned cache directory under %LOCALAPPDATA% instead of hard failing on %USERPROFILE%\.cache. The current UI only shows the generic readiness-check failure, which makes diagnosis much harder.