Add app source and tests

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

lib/Peach/see/systemd/ViewSystemd.dart

@@ -0,0 +1,68 @@
+import '../../about/external/initial/SystemdSpec.dart';
+import '../../about/internal/application/ServerProfile.dart';
+import '../../about/internal/application/ServiceConfig.dart';
+import '../../about/internal/application/StepTracker.dart';
+import '../../comms/Comms.dart' show LogLine;
+import '../parent/ParentViewModel.dart';
+import 'ConnectSystemd.dart';
+
+class ViewSystemd extends ParentViewModel {
+  ConnectSystemd connection;
+
+  ViewSystemd(super.context, this.connection);
+
+  Stream<LogLine> get logs => getDataManager().logs;
+
+  Stream<List<DeployStep>> get steps => getDataManager().stepStream;
+
+  /// Writes the unit file, reloads systemd and (optionally) enables and starts
+  /// it. On success the unit name is recorded against [service] so the deploy
+  /// and log screens target the right unit from now on.
+  void installUnit(
+    ServerProfile server,
+    SystemdSpec spec,
+    ServiceConfig? service,
+  ) async {
+    if (!await canReach(server, () => installUnit(server, spec, service))) {
+      return;
+    }
+    try {
+      final result = await getDataManager().installSystemdUnit(
+        server: server,
+        unitName: spec.safeName,
+        unitContent: spec.render(),
+        enable: spec.enableOnBoot,
+        startNow: spec.startNow,
+      );
+
+      if (result.ok && service != null) {
+        service.serviceName = spec.safeName;
+        await _persistService(server, service);
+      }
+
+      connection.onUnitInstalled(result);
+    } catch (error) {
+      handleError(
+        error,
+        () => installUnit(server, spec, service),
+        () {},
+        "Retry",
+      );
+    }
+  }
+
+  /// Saves the service back onto its server in storage.
+  Future<void> _persistService(
+    ServerProfile server,
+    ServiceConfig service,
+  ) async {
+    final servers = await getDataManager().getServers();
+    final serverIndex = servers.indexWhere((s) => s.id == server.id);
+    if (serverIndex < 0) return;
+    final services = servers[serverIndex].services;
+    final serviceIndex = services.indexWhere((s) => s.id == service.id);
+    if (serviceIndex < 0) return;
+    services[serviceIndex] = service;
+    await getDataManager().setServers(servers);
+  }
+}