The test left freeBelowBytes at its 50 GiB default, so on a disk with under
50 GiB free the content cache's limit fell to zero. Downloading another photo
then evicted photo 1's cached original, and the test fetched it a fourth time
instead of copying it. Both of its libraries now open with freeBelowBytes: 0.
Every other test that opens a library or content cache with the real free
space was read; none has a result that depends on it. The 50 GiB default is
unchanged.
Model: opus-5-5