Mejoras de estabilidad de stream IPTV y nuevo registro de fallos

- restream.py: eliminar -reconnect_streamed de ffmpeg para evitar rebobinados
  al reconectar (el proveedor re-enviaba desde keyframe anterior causando PTS
  backward). El loop de Python gestiona las reconexiones con conexión fresca.
- restream.py: eliminar _drain_queue del loop de reconexión para que el buffer
  de la cola cubra el tiempo de reconexión sin pantalla negra en el player.
- restream.py: añadir buffer_server_bytes/secs/capacity a stats() y método
  _log_stream_event() para persistir eventos de caída y recuperación en BD.
- models/stream_event.py: nuevo modelo StreamEvent para registro de fallos.
- database.py: registrar StreamEvent en init_db.
- api/admin/logs.py: nuevos endpoints GET/DELETE /logs/events.
- Dashboard.tsx: mostrar reserva de buffer del servidor (capacidad + estado).
- Logs.tsx: añadir pestaña "Fallos de stream" con tabla de eventos persistidos.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/models/jellyfin.py

@@ -0,0 +1,47 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, Text, ForeignKey, func
+from sqlalchemy.orm import relationship
+from ..database import Base
+
+
+class JellyfinConfig(Base):
+    __tablename__ = "jellyfin_configs"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(200), nullable=False)
+    url = Column(String(500), nullable=False)
+    api_key = Column(String(300), nullable=False)
+    is_active = Column(Boolean, default=True, nullable=False)
+    movies_library_id = Column(String(100), nullable=True)
+    series_library_id = Column(String(100), nullable=True)
+    movies_category_name = Column(String(200), default="Películas KiraTV", nullable=False)
+    series_category_name = Column(String(200), default="Series KiraTV", nullable=False)
+    last_sync_at = Column(DateTime(timezone=True), nullable=True)
+    # Dummy ProviderAccount auto-created to satisfy ChannelProviderMap FK
+    provider_account_id = Column(
+        Integer,
+        ForeignKey("provider_accounts.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+
+    items = relationship("JellyfinItem", back_populates="config", cascade="all, delete-orphan")
+
+
+class JellyfinItem(Base):
+    __tablename__ = "jellyfin_items"
+
+    id = Column(Integer, primary_key=True, index=True)
+    jellyfin_config_id = Column(
+        Integer, ForeignKey("jellyfin_configs.id", ondelete="CASCADE"), nullable=False
+    )
+    channel_id = Column(
+        Integer, ForeignKey("channels.id", ondelete="CASCADE"), nullable=True
+    )
+    jellyfin_item_id = Column(String(100), nullable=False, index=True)  # Jellyfin hex ID
+    item_type = Column(String(20), nullable=False)  # "movie" | "series"
+    plot = Column(Text, nullable=True)
+    year = Column(Integer, nullable=True)
+    genres = Column(String(500), nullable=True)
+    rating = Column(String(20), nullable=True)
+
+    config = relationship("JellyfinConfig", back_populates="items")