Initial site mode stuff

lib/game/sitemode/sitemode.dart

@@ -0,0 +1,23 @@
+import 'package:dartterm/algorithms/geometry.dart' as geo;
+import 'package:dartterm/terminal.dart';
+import 'package:dartterm/world/level.dart';
+
+Future<void> sitemode(Level level) async {
+  await _SiteMode(level).start();
+}
+
+class _SiteMode {
+  Level level;
+  late geo.Offset position;
+
+  _SiteMode(this.level) {
+    position = level.spawn;
+  }
+
+  Future<void> start() async {
+    while (true) {
+      at(0, 0).puts("Site mode!");
+      await zzz(0.1);
+    }
+  }
+}