Function is_lossless_adapter 

pub fn is_lossless_adapter(from: PortType, to: PortType) -> bool

Classify a catalog adapter as lossless or lossy per expression_engine.md §5.4.3. Lossless conversions preserve value identity (widening numeric types, to-string display roundtrips); lossy conversions change information content (truncation, boolean projection).

Strict-mode embedding surfaces use this to gate which catalog adapters they’ll invoke.