Add app source and tests

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

lib/Peach/see/health/ConnectHealth.dart

@@ -0,0 +1,13 @@
+import '../../about/external/data/Health.dart';
+
+abstract class ConnectHealth {
+  /// Every known service was marked as pending a check.
+  void onSweepStarted();
+
+  /// One service's check came back. Results arrive as they complete rather
+  /// than in a single batch, so the dashboard fills in progressively.
+  void onServiceChecked(String serviceId, HealthResult result);
+
+  /// All services in this sweep have been checked.
+  void onSweepFinished();
+}