feat: add health check endpoints for Bot and Web

- Web: add /health endpoint with PostgreSQL readiness check (returns 200+JSON or 503)
- Web: add /alive endpoint for liveness probe
- Bot: add BotHealthCheckHostedService serving /health on port 8081 via HttpListener
- Bot: expose port 8081 in Dockerfile and install wget for healthcheck
- compose.yaml: add healthcheck sections for bot and web services
- tests: add TDD tests for both health endpoints

Bump version -> 1.16.0

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/GmRelay.Bot/Dockerfile

@@ -30,9 +30,15 @@ RUN dotnet publish "GmRelay.Bot.csproj" -c Release -a $TARGETARCH -o /app/publis
 FROM mcr.microsoft.com/dotnet/runtime-deps:10.0-noble AS final
 WORKDIR /app
 
+# Устанавливаем wget для healthcheck
+RUN apt-get update && apt-get install -y --no-install-recommends wget \
+    && rm -rf /var/lib/apt/lists/*
+
 # Копируем только AOT-результаты из билда
 COPY --from=build /app/publish .
 
+EXPOSE 8081
+
 USER $APP_UID
 
 # Запуск скомпилированного AOT бинарного файла напрямую