Reuse persisted provider/model settings by creating missing local, remote, or custom engines on first embedding use instead of requiring memory_set_model on every connection.
Keep memory_set_model eager so callers can preload and validate engines explicitly, while memory_set_apikey remains connection-scoped and lazy for saved remote models.
Update API/README documentation and add regression coverage for saved local, remote, and custom provider settings.
Verification: build/unittest with TEST_SQLITE_EXTENSION passed 157 tests.
Reuse persisted provider/model settings by creating missing local, remote, or custom engines on first embedding use instead of requiring memory_set_model on every connection.
Keep memory_set_model eager so callers can preload and validate engines explicitly, while memory_set_apikey remains connection-scoped and lazy for saved remote models.
Update API/README documentation and add regression coverage for saved local, remote, and custom provider settings.
Verification: build/unittest with TEST_SQLITE_EXTENSION passed 157 tests.