Add app source and tests

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

lib/Peach/see/files/ConnectFiles.dart

@@ -0,0 +1,18 @@
+import '../../comms/Comms.dart' show RemoteEntry;
+
+abstract class ConnectFiles {
+  /// The user's home directory, resolved on open — the starting location.
+  void onHomeResolved(String path);
+
+  /// The contents of the directory currently being shown.
+  void onDirectoryLoaded(List<RemoteEntry> entries);
+
+  /// The listing failed; [message] explains why.
+  void onDirectoryFailed(String message);
+
+  /// A transfer finished (or failed) with a message to surface.
+  void onTransferFinished(String message);
+
+  /// A remote entry was deleted.
+  void onEntryDeleted();
+}