Add public facade value wrappers

internal/facade/diagnostic.go

@@ -0,0 +1,44 @@
+package configkit
+
+import (
+	"io"
+
+	"gitea.maximumdirect.net/eric/ConfigKit/internal/engine"
+)
+
+// LoadError reports safe structured diagnostics for a failed configuration load.
+type LoadError struct{ value *engine.LoadError }
+
+func (e *LoadError) Error() string {
+	if e == nil || e.value == nil {
+		return "configkit: configuration load failed"
+	}
+	return e.value.Error()
+}
+func (e *LoadError) Diagnostics() []Diagnostic {
+	if e == nil || e.value == nil {
+		return nil
+	}
+	values := e.value.Diagnostics()
+	result := make([]Diagnostic, len(values))
+	for i := range values {
+		result[i] = fromEngineDiagnostic(values[i])
+	}
+	return result
+}
+func (e *LoadError) Sources() []SourceInfo {
+	if e == nil || e.value == nil {
+		return nil
+	}
+	values := e.value.Sources()
+	result := make([]SourceInfo, len(values))
+	for i := range values {
+		result[i] = fromEngineSourceInfo(values[i])
+	}
+	return result
+}
+
+// WriteDiagnostics writes diagnostics in canonical order.
+func WriteDiagnostics(output io.Writer, diagnostics []Diagnostic) error {
+	return engine.WriteDiagnostics(output, toEngineDiagnostics(diagnostics))
+}