Use tcp health check

cicd/docker/Dockerfile.backend

@@ -19,7 +19,6 @@ RUN dotnet publish "src/backend/src/Randall.Api/Randall.Api.csproj" \
 FROM mcr.microsoft.com/dotnet/aspnet:10.0 AS runtime
 WORKDIR /app
 
-RUN apt-get update && apt-get install -y --no-install-recommends curl && rm -rf /var/lib/apt/lists/*
 RUN mkdir -p /app/data
 COPY --from=build /app/publish .
 

cicd/docker/docker-compose.yml

@@ -13,7 +13,7 @@ services:
       - db-data:/app/data
     restart: unless-stopped
     healthcheck:
-      test: ["CMD", "curl", "-f", "http://localhost:8080/health"]
+      test: ["CMD-SHELL", "bash -c '</dev/tcp/localhost/8080'"]
       interval: 10s
       timeout: 5s
       retries: 5