fix(infra): use CMD-SHELL with /dev/tcp for health check

- Alpine-based image doesn't have curl
- CMD-SHELL provides bash with /dev/tcp support
- No external package installation needed

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

GermanApp/Dockerfile

@@ -36,9 +36,6 @@ FROM build AS publish
 FROM mcr.microsoft.com/dotnet/aspnet:9.0 AS runtime
 WORKDIR /app
 
-# Install curl for health checks (Alpine-based image doesn't include it)
-RUN apk add --no-cache curl
-
 # Copy published app from publish stage
 COPY --from=publish /app/publish .
 
@@ -50,9 +47,9 @@ ENV ASPNETCORE_ENVIRONMENT=Production
 # Expose port
 EXPOSE 8080
 
-# Health check
-HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
-    CMD curl -f http://localhost:8080/health || exit 1
+# Health check - use CMD-SHELL for bash /dev/tcp support
+HEALTHCHECK --interval=30s --timeout=3s --start-period=15s --retries=3 \
+    CMD-SHELL echo > /dev/tcp/localhost/8080 || exit 1
 
 # Entry point
 ENTRYPOINT ["dotnet", "GermanApp.dll"]