Add retryable normalization fallbacks

internal/framework/contracts/errors.go

@@ -0,0 +1,7 @@
+package contracts
+
+import "errors"
+
+// ErrInvalidStructuredOutput identifies a provider response that cannot satisfy
+// the caller's declared structured-output contract.
+var ErrInvalidStructuredOutput = errors.New("invalid structured output")

internal/framework/contracts/typed_pipeline.go

@@ -90,6 +90,15 @@ type TypedNormalizeRequest[T any] struct {
 type TypedNormalizeResult[T any] struct {
 	Value    T
 	Warnings []Warning
+	Retry    *NormalizeRetry
+}
+
+// NormalizeRetry asks the framework to retry normalization while retaining a
+// safe candidate for acceptance if the retry budget is exhausted.
+type NormalizeRetry struct {
+	ReasonCode       string
+	Message          string
+	FallbackWarnings []Warning
 }
 
 type Normalizer[T any] interface {