Requests and the eviction pass write on separate connections, and with
no busy timeout a write that met another one failed at once with
"database is locked" and was lost. internal/database now adds
_pragma=busy_timeout(5000) to every db_url, the default or one the
operator sets, so such a write waits up to five seconds. The default
db_url's _journal_mode=WAL is not a parameter the driver reads, so it
is now _pragma=journal_mode(WAL). README.md and config.example.yml say
what pixa adds to db_url.
Model: opus-5-5
