Per-run module cache network analytics on the run detail page

Each run’s Module Cache tab now shows the network side of the binary cache alongside its hit rate. The Summary card reports total bytes downloaded and uploaded for prebuilt modules, while the Module Cache card shows a time-weighted download and upload throughput, presented the same way as the Xcode Cache (CAS Outputs) view. This makes it easier to spot runs where the remote module cache fetch was slow or only partial, which is the main lever left to optimize once hit rate is already high, especially on CI.