Initial commit: two Clojure Android todo apps

Side-by-side comparison of viable Clojure-on-Android approaches:
- todo-expo/: ClojureScript + shadow-cljs + Expo + Reagent + re-frame
- todo-flutter/: ClojureDart + Flutter

Both apps feature: add/remove/check-off todos, SQLite persistence,
categories, priorities, edit support, swipe-to-delete, filtering.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

todo-flutter/test/widget_test.dart

@@ -0,0 +1,13 @@
+// Placeholder test file for ClojureDart Todo app.
+// ClojureDart compiles to Dart, and tests are typically
+// written in ClojureDart using cljd.test.
+
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('App compiles successfully', (WidgetTester tester) async {
+    // ClojureDart apps are tested via the ClojureDart test framework.
+    // This placeholder verifies the test infrastructure works.
+    expect(true, isTrue);
+  });
+}