feat(display): Sprint 4 — pantalla principal del autopilot

Archivos nuevos:
  display/lib/data/autopilot_state.dart
    - ChangeNotifier con todos los datos del autopilot
    - Simulación de velero en mar (heading drift / P-controller)
    - API pública estable: engage(), disengage(), adjustSetpoint(), selectMode()
    - Sprint 7: los internos se reemplazan por Modbus RTU, la API no cambia

  display/lib/screens/cockpit/cockpit_screen.dart
    - Pantalla principal: TopBar, ModeSelector, CompassRose, DataStrip,
      HeadingAdjustBar, RudderIndicator, ENGAGE/DISENGAGE
    - Logo con triple-tap para ciclar temas (StateWidget con Timer)
    - Indicador DEMO visible cuando isConnected == false
    - Engranaje → AppearanceSettingsScreen

  display/lib/widgets/themed/engage_button.dart
    - Botón verde con glow; dimmed cuando ya está engaged

  display/lib/widgets/themed/heading_adjust_bar.dart
    - Botones << < [SET 048.0°] > >>
    - Deshabilitado cuando mode == STANDBY

  display/lib/widgets/themed/status_chip.dart
    - Indicador de punto + label para NMEA / GPS (ok / warn / off)

Modificado:
  display/lib/main.dart
    - MultiProvider: agrega AutopilotState al árbol de providers
    - Ruta inicial: CockpitScreen.routeName ('/') en lugar de Appearance

AR_electronics — AR-Autopilot Project

display/lib/main.dart

@@ -1,15 +1,27 @@
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
+import 'data/autopilot_state.dart';
 import 'theme/theme_provider.dart';
+import 'screens/cockpit/cockpit_screen.dart';
 import 'screens/settings/appearance_settings.dart';
 
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
   final themeProvider = await AutopilotThemeProvider.load();
   runApp(
-    ChangeNotifierProvider<AutopilotThemeProvider>.value(
-      value: themeProvider,
+    MultiProvider(
+      providers: [
+        ChangeNotifierProvider<AutopilotThemeProvider>.value(
+          value: themeProvider,
+        ),
+        // AutopilotState drives the cockpit UI.
+        // Sprint 4: internal demo timer (vessel simulation).
+        // Sprint 7: replace with AutopilotStateModbus or wire Modbus RTU here.
+        ChangeNotifierProvider<AutopilotState>(
+          create: (_) => AutopilotState(),
+        ),
+      ],
       child: const ArAutopilotApp(),
     ),
   );
@@ -24,10 +36,11 @@ class ArAutopilotApp extends StatelessWidget {
       title: 'AR-Autopilot',
       debugShowCheckedModeBanner: false,
       theme: ThemeData(useMaterial3: true),
-      // Initial route — Sprint 4 starts with the Appearance screen for demo
-      initialRoute: AppearanceSettingsScreen.routeName,
+      initialRoute: CockpitScreen.routeName,
       routes: {
-        AppearanceSettingsScreen.routeName: (_) => const AppearanceSettingsScreen(),
+        CockpitScreen.routeName: (_) => const CockpitScreen(),
+        AppearanceSettingsScreen.routeName: (_) =>
+            const AppearanceSettingsScreen(),
       },
     );
   }