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-expo/.gitignore

@@ -0,0 +1,22 @@
+node_modules/**/*
+.expo/*
+npm-debug.*
+*.jks
+*.p12
+*.key
+*.mobileprovision
+out/
+.shadow-cljs/
+.nrepl-port
+pom.xml
+.idea/
+*.iml
+app
+.cpcache
+/web-build
+.calva/output-window/
+.DS_Store
+
+.lsp/.cache
+.clj-kondo/.cache
+.lsp/sqlite.db