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.

openspec/changes/startup-retry-custom-stations-eq-persistence/state.yaml

@@ -0,0 +1,48 @@
+schema: spec-driven
+change: startup-retry-custom-stations-eq-persistence
+project: pluriwave
+artifact_store: hybrid
+execution_mode: auto
+strict_tdd: true
+test_command: flutter test
+build_command: null
+current_phase: apply-partial
+next_recommended: sdd-verify
+phases:
+  explore:
+    status: completed
+    file: openspec/changes/startup-retry-custom-stations-eq-persistence/explore.md
+    engram_topic_key: sdd/startup-retry-custom-stations-eq-persistence/explore
+  proposal:
+    status: completed
+    file: openspec/changes/startup-retry-custom-stations-eq-persistence/proposal.md
+    engram_topic_key: sdd/startup-retry-custom-stations-eq-persistence/proposal
+  spec:
+    status: completed
+    file: openspec/changes/startup-retry-custom-stations-eq-persistence/spec.md
+    engram_topic_key: sdd/startup-retry-custom-stations-eq-persistence/spec
+  design:
+    status: completed
+    file: openspec/changes/startup-retry-custom-stations-eq-persistence/design.md
+    engram_topic_key: sdd/startup-retry-custom-stations-eq-persistence/design
+  tasks:
+    status: completed
+    file: openspec/changes/startup-retry-custom-stations-eq-persistence/tasks.md
+    engram_topic_key: sdd/startup-retry-custom-stations-eq-persistence/tasks
+  apply:
+    status: partial
+    file: openspec/changes/startup-retry-custom-stations-eq-persistence/apply-progress.md
+    engram_topic_key: sdd/startup-retry-custom-stations-eq-persistence/apply-progress
+  verify:
+    status: pending
+  archive:
+    status: pending
+constraints:
+  - Do not implement production code during planning.
+  - Do not run flutter build.
+  - Apply strict TDD: write failing tests before production changes.
+  - Preserve Spanish folder/naming style and Provider/ChangeNotifier patterns.
+risks:
+  - Retry policy must not block startup for too long.
+  - Native equalizer availability is platform/runtime dependent.
+  - Current station tracking must be fixed for station-specific EQ to be reliable.