A minimal r2d2::ManageConnection for rusqlite. Hand-written instead of
depending on the r2d2_sqlite crate: that crate pins its own rusqlite
version, which never lines up with the rusqlite version ling-ai
already pulls in transitively (via the burn ML framework) — and two
different rusqlite/libsqlite3-sys versions can’t coexist in one
Cargo.lock (both declare links = "sqlite3"). r2d2 itself has no
sqlite dependency, so implementing this ourselves keeps us on exactly
one rusqlite version, chosen by us, everywhere in the workspace.