Production reads DATABASE_URL (postgres://) through @profullstack/libsql-pg,
which keeps the @libsql/client surface; no query changed. A missing,
non-Postgres or leftover libsql:// URL fails at boot in production. Dev and
tests keep libSQL (file:/:memory:) as a devDependency. Postgres migrations in
src/migrations-pg/ (converted with libsql-pg convert-schema, same file names
so the copied _migrations ledger matches); migrate.mjs picks the dialect.
Tests run against Postgres with PWA_TEST_DATABASE_URL.
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
