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/windows/.gitignore

@@ -0,0 +1,17 @@
+flutter/ephemeral/
+
+# Visual Studio user-specific files.
+*.suo
+*.user
+*.userosscache
+*.sln.docstates
+
+# Visual Studio build-related files.
+x64/
+x86/
+
+# Visual Studio cache files
+# files ending in .cache can be ignored
+*.[Cc]ache
+# but keep track of directories ending in .cache
+!*.[Cc]ache/