Second CI run on Windows:
- gallery roots are stored resolved and case-folded there; the admin API
tests now compare against that form instead of the mixed-case temp path
- the subfolder fallback for images outside every root also uses "/", and
the test expects it
- a relative diagnostics db path is normalised after joining
- "database is locked" under many writers on a slow disk: connections now
wait up to 30 seconds (connect timeout and busy_timeout), long enough for
a scan or thumbnail run while ComfyUI saves images