fix: Remove default nginx files before copying Blazor WASM output

- nginx:alpine has default index.html that prevents Blazor from loading
- Added RUN rm -rf /usr/share/nginx/html/* before COPY

src/BackOffice/Dockerfile

@@ -19,6 +19,9 @@ RUN dotnet publish "BackOffice.csproj" -c Release -o /app/publish
 FROM nginx:alpine AS final
 WORKDIR /usr/share/nginx/html
 
+# Remove default nginx files
+RUN rm -rf /usr/share/nginx/html/*
+
 # Copy published wwwroot (Blazor WASM output)
 COPY --from=build /app/publish/wwwroot .