SQLite data source, built on Lotus.Source.Adapters.Ecto.
Resolved automatically for any repo whose Ecto adapter is
Ecto.Adapters.SQLite3, so hosts normally never name this module —
they configure the repo and Lotus wraps it.
Dialect behaviour comes from
Lotus.Source.Adapters.Ecto.Dialects.SQLite3: a flat namespace (no schemas) and EXPLAIN QUERY PLAN query plans.