Fix wording, docs and style inconsistencies per audit of 0139564

internal/workflow/parse.go

@@ -14,7 +14,7 @@ func Parse(data []byte) (api.WorkflowDefinition, error) {
 	dec.DisallowUnknownFields()
 	err := dec.Decode(&def)
 	if err != nil {
-		return api.WorkflowDefinition{}, fmt.Errorf("%w: %v", ErrInvalid, err)
+		return api.WorkflowDefinition{}, fmt.Errorf("%w: %w", ErrInvalid, err)
 	}
 	return def, Validate(def)
 }