Add Flutter project skeleton (Android-only MVP)

Five-layer architecture per DMC_Architektur_und_Design.md: FlightControllerLink
abstraction (Mock + MSP stub), protocol-neutral mission domain layer, App-Mode
state machine with Ready-to-Fly gate, Drift persistence schema, and placeholder
UI screens wired via go_router. App icon generated from design/Y2_pink_dark.svg.
Verified with flutter analyze and flutter test.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/lib/transport/flight_controller_link.dart

@@ -0,0 +1,57 @@
+import '../domain/waypoint/flat_waypoint_list.dart';
+
+/// Abstrakte Flugmodi, protokollunabhaengig (Architektur-Doku 3.1).
+enum FlightMode { missionRun, guidedPoint, returnHome, hold }
+
+/// Feature-Flags des angebundenen Flightcontrollers (Doku 3.1).
+class FcCapabilities {
+  const FcCapabilities({
+    required this.supportsMultiMission,
+    required this.supportsInFlightUpload,
+    required this.maxWaypoints,
+  });
+
+  final bool supportsMultiMission;
+  final bool supportsInFlightUpload;
+  final int maxWaypoints;
+}
+
+/// Normalisiertes Telemetrie-Frame, das an die UI weitergereicht wird (Doku 3.4).
+class TelemetryFrame {
+  const TelemetryFrame({
+    required this.lat,
+    required this.lon,
+    required this.altitudeM,
+    required this.speedMs,
+    required this.armed,
+    this.activeWaypointIndex,
+  });
+
+  final double lat;
+  final double lon;
+  final double altitudeM;
+  final double speedMs;
+  final bool armed;
+  final int? activeWaypointIndex;
+}
+
+/// Zentrale Abstraktion fuer alle Flightcontroller-Interaktionen (Doku 3.1).
+/// Implementierungen: MspFlightControllerLink (iNAV), MavlinkFlightControllerLink
+/// (ArduPilot, Post-MVP), MockFlightControllerLink (Tests ohne Hardware).
+abstract class FlightControllerLink {
+  FcCapabilities get capabilities;
+
+  Future<void> connect();
+
+  Future<void> disconnect();
+
+  Future<void> uploadMission(FlatWaypointList mission);
+
+  Future<void> setFlightMode(FlightMode mode);
+
+  Future<void> arm();
+
+  Stream<TelemetryFrame> subscribeTelemetry();
+
+  Future<int?> readActiveWaypointIndex();
+}