feat: add Statements, the top-level statement iterator

Assisted-by: GLM 5.3 Flash

examples/statements/main_test.go

@@ -0,0 +1,39 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: MIT
+
+package main
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestStatementsExample(t *testing.T) {
+	in := strings.NewReader(`title = "demo"
+port = 8080
+
+[server]
+host = "127.0.0.1"
+
+[[items]]
+name = "a"
+
+[[items]]
+name = "b"
+`)
+	var out strings.Builder
+	if err := run(in, &out); err != nil {
+		t.Fatal(err)
+	}
+	for _, want := range []string{
+		"title = demo",
+		"port = 8080",
+		"[server] keys: [host]",
+		"[[items]] #0",
+		"[[items]] #1",
+	} {
+		if !strings.Contains(out.String(), want) {
+			t.Errorf("output missing %q:\n%s", want, out.String())
+		}
+	}
+}