Add TV bumpers functionality: introduce configuration options for bumpers in .env.example and appsettings.json, enhance ChannelEndpoints to manage jingles and bumper assets, and update Channel and ScheduleEntry models to support bumper logic. Implement validation for bumper settings and integrate bumper handling in scheduling logic.

Dockerfile

@@ -26,8 +26,9 @@ RUN dotnet publish backend/src/TeleWave.Api/TeleWave.Api.csproj -c Release -o /a
 # ── Stage 3: runtime ──────────────────────────────────────────────────────
 FROM mcr.microsoft.com/dotnet/aspnet:10.0 AS runtime
 WORKDIR /app
-# curl — для HEALTHCHECK; ffmpeg — нормализация и нарезка медиа при загрузке (см. Media__FfmpegPath).
-RUN apt-get update && apt-get install -y --no-install-recommends curl ffmpeg \
+# curl — для HEALTHCHECK; ffmpeg — нормализация и нарезка медиа при загрузке (см. Media__FfmpegPath);
+# fonts-dejavu-core — кириллический TTF для текста на ТВ-заставках (drawtext, см. Bumpers__FontFile).
+RUN apt-get update && apt-get install -y --no-install-recommends curl ffmpeg fonts-dejavu-core \
     && rm -rf /var/lib/apt/lists/*
 ENV ASPNETCORE_ENVIRONMENT=Production \
     ASPNETCORE_HTTP_PORTS=8080