feat(sourcetest): add -v flag with verbose manga list output

When -v is passed, test-sources.sh passes it through to go test -v.
sourcetest.Run uses testing.Verbose() to print the full manga list
from GetPopularManga and GetLatestUpdates, showing title + URL.

.env.example

@@ -8,6 +8,7 @@ DATABASE_URL=postgres://goyomi:goyomi@postgres:5432/goyomi?sslmode=disable
 FLARESOLVERR_URL=http://flaresolverr:8191
 FLARESOLVERR_LOG_LEVEL=info
 FLARESOLVERR_PROXY=0
+FLARESOLVERR_SESSION=goyomi
 ADDR=:3300
 
 # Connection pool