feat: Implement startup retry mechanism for custom stations and equalizer persistence

- Added state management for startup retry and custom station handling in `EstadoRadio`.
- Created tasks for implementing strict TDD with RED tests for HTTP failure retries and EQ persistence.
- Developed verification report to ensure compliance with TDD practices.
- Introduced fake services for testing, including `FakeServicioAudio`, `FakeServicioFavoritos`, and `FakeServicioRadio`.
- Implemented widget tests for `PantallaInicio` and `PantallaFavoritos` to validate UI behavior with custom stations.
- Enhanced `ServicioRadio` to support host rotation and retry logic for API calls.
- Established a new configuration file to enforce project constraints and testing rules.

test/servicios/servicio_radio_test.dart

@@ -0,0 +1,72 @@
+import 'dart:convert';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
+import 'package:pluriwave/servicios/servicio_radio.dart';
+
+void main() {
+  group('ServicioRadio retry + rotación', () {
+    test(
+        'reintenta con otro host cuando el primero falla y recupera en el segundo',
+        () async {
+      final hostsSolicitados = <String>[];
+      final servicio = ServicioRadio(
+        cliente: MockClient((request) async {
+          hostsSolicitados.add(request.url.host);
+          if (request.url.host == 'host-1.api.radio-browser.info') {
+            return http.Response('fallo', 500);
+          }
+          return http.Response(
+            jsonEncode([
+              {
+                'stationuuid': 'uuid-ok',
+                'name': 'Radio Recuperada',
+                'url_resolved': 'https://stream.recuperada/audio',
+              },
+            ]),
+            200,
+            headers: {'content-type': 'application/json'},
+          );
+        }),
+        servidores: const [
+          'host-1.api.radio-browser.info',
+          'host-2.api.radio-browser.info',
+        ],
+        maxIntentos: 3,
+        retryDelay: Duration.zero,
+      );
+
+      final emisoras = await servicio.obtenerPopulares(limit: 1);
+
+      expect(emisoras, hasLength(1));
+      expect(emisoras.first.uuid, 'uuid-ok');
+      expect(
+        hostsSolicitados,
+        equals([
+          'host-1.api.radio-browser.info',
+          'host-2.api.radio-browser.info',
+        ]),
+      );
+    });
+
+    test('corta al llegar al tope de intentos y propaga error final', () async {
+      var intentos = 0;
+      final servicio = ServicioRadio(
+        cliente: MockClient((request) async {
+          intentos += 1;
+          throw http.ClientException('sin red', request.url);
+        }),
+        servidores: const ['host-unico.api.radio-browser.info'],
+        maxIntentos: 2,
+        retryDelay: Duration.zero,
+      );
+
+      expect(
+        () => servicio.obtenerPopulares(limit: 1),
+        throwsA(isA<Exception>()),
+      );
+      expect(intentos, 2);
+    });
+  });
+}