Module error 

Typed error and warning surface — PDD §8.

Errors are a real enum from day one (no stringly-typed codes), so tests can assert exact variants and the SW→error mapping can be exhaustively checked. The v0.5 category prefixes (T_/S_/K_/C_/L_/P_/I_/V_) survive only as the comment groupings below.

no_std: the thiserror::Error derive is kept — error_in_core is stable since Rust 1.81, and thiserror ≥2 with default-features = false derives core::error::Error. Former String/Vec<u8> payloads are fixed-capacity heapless collections sized from crate::limits.

Structs

Warning

Non-fatal warning attached to a report’s warnings (PDD §7/§8).

Enums

BackendError

Coarse error surface returned by every backend trait method (PDD §3.3/§8). Carries an opaque detail so software and HSM/PKCS#11 backends can attach context without leaking key material.

ScllError

Fatal error returned by every public workflow function (Result<XReport, ScllError>).

WarningKind

Typed warning kinds (PDD §8). No String codes.