Add Go transcript and glossary schemas

internal/core/schema/errors.go

@@ -0,0 +1,23 @@
+package schema
+
+import "fmt"
+
+type ParseError struct {
+	Message string
+}
+
+func (e *ParseError) Error() string {
+	return e.Message
+}
+
+type ValidationError struct {
+	Field   string
+	Message string
+}
+
+func (e *ValidationError) Error() string {
+	if e.Field != "" {
+		return fmt.Sprintf("%s: %s", e.Field, e.Message)
+	}
+	return e.Message
+}