Module confidence 

Confidence — Phase D audit-provenance payload.

Every FixProposal carries a Confidence record describing how the engine arrived at the proposal. The record stores two primary scalar confidence axes — recognition and rule — plus optional auxiliary fields (region and runner_up_ratio) and a list of named feature contributions. Together they reconstruct the decoder’s scoring path so an auditor can verify why a given fix was promoted.

The engine’s current threshold-facing combined score is recognition * rule as exposed by Confidence::combined. region is recorded as additional audit/context metadata when available, but it does not currently participate in that combined score. runner_up_ratio likewise provides decoder provenance rather than a direct multiplicative/additive input to combined().

Precision: f32 throughout

All scores are f32. The decoder scores in f64 internally (log-priors and posteriors accumulate across many features), but the emitted Confidence downcasts once at the boundary so the audit record stays compact and byte-stable. This matches the foundational-plan invariant line 739-757.

features is closed

FeatureId is a non-#[non_exhaustive] closed enum. A new feature means a new variant and a coordinated bump of the audit schema version (MARQUE_AUDIT_SCHEMA) — silent additions would break the auditability contract on already-emitted records.

Structs

Confidence

Multi-axis confidence attached to every FixProposal.

FeatureContribution

One named contribution to Confidence::recognition.

Enums

FeatureId

Closed enumeration of features the decoder can record.