Add app source and tests

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

lib/Peach/informatics/DataManager.dart

@@ -0,0 +1,10 @@
+import '../about/internal/file/ConnectFileStorage.dart';
+import '../comms/ConnectComms.dart';
+import '../memory/ConnectInternalMemory.dart';
+
+/// The single gateway every ViewModel talks to. It is the union of the three
+/// capability contracts — remote (SSH), local persistence, and local files — so
+/// a screen never reaches for a service directly and no screen needs to know
+/// which of the three a given call lands on.
+abstract class DataManager
+    implements ConnectInternalMemory, ConnectComms, ConnectFileStorage {}