SQLite — adding foreign keys:ddl::create_constraints_sql_with_dialect emits ALTER TABLE … ADD CONSTRAINT FOREIGN KEY, which SQLite's parser rejects (FK
constraints must be inline at CREATE TABLE). The sqlite_orm_demo
example skips that loop on SQLite. A fuller fix would move FK
constraints into the inline column list when the dialect doesn't
support ALTER-style FK addition.
SQLite — apply_all_pool and framework models:apply_all_pool walks the full inventory::registered_models()
list, which on a default build includes framework models (Org,
Operator, Job, …) whose DDL emits Postgres-shape SQL that fails on
SQLite. The demo emits DDL by hand for just its own models. A
Dialect::supports_model(&ModelSchema) filter would let
apply_all_pool skip incompatible models cleanly.