Nearly all of the package's test time was SQLite work, and much of it
was setup every test repeated: each test migrated a fresh schema, and
each new session wrote the seven-line default MOTD to the database.
TestMain now migrates one in-memory template database once, and each
test starts from its own copy of it, made with SQLite's backup API.
The test config's MOTD is one line. Every test still gets an empty
database of its own, and every check runs as before.
Model: opus-5-5
