tests/__init__.py keeps a run offline, its scratch under tmp/ and its
installer cache its own, but only discover -s tests -t . imported it.
discover tests ran with RETROBIOS_OFFLINE unset, scratch on the /tmp
tmpfs and the user's real installer cache, the setting in which e2e
fixtures had written into the shared .cache/large. Every test module now
imports the package first, and a test fails on a module that does not.
test_verify_listing.py took its line with the previous commit.
files/?sha1= of a file the collection no longer holds answered that no
file the site knows has the hash. generate_db.py now records each sha1 a
rebuild drops in retired.json, with the day and the file in its place,
backfilled from the history since 0d586ef6b (4,139 files). The lookup
answers with it and leads to the successor's card.