Show messages for builds and large downloads in non-interactive mode (#11165)
When stderr is not a tty, we currently don't show any messages for build
or large downloads, since indicatif is hidden. We can improve this by
showing a message for:
* Starting and finishing a large download (>1MB)
* Starting and finishing a build
Downloads are limited to 1MB or unknown size to keep the logs concise
and not scroll the entire terminal away for a download that finishes
almost immediately.
These messages are not captured in the tests since their order is
non-deterministic (downloads and builds race to finish).
There are no "tick" messages for large downloads yet, we could e.g. show
an update on runnning downloads every n seconds.
Part of #11121
**Test Plan**
```
$ uv venv && FORCE_COLOR=1 cargo run -q pip install numpy --no-binary :all: --no-cache 2>&1 | tee a.txt
Using CPython 3.13.0
Creating virtual environment at: .venv
Activate with: source .venv/bin/activate
Resolved 1 package in 221ms
Building numpy==2.2.2
Built numpy==2.2.2
Prepared 1 package in 2m 34s
Installed 1 package in 6ms
+ numpy==2.2.2
```

```
$ uv venv && FORCE_COLOR=1 cargo run -q pip install torch --no-cache 2>&1 | tee b.txt
Using CPython 3.13.0
Creating virtual environment at: .venv
Activate with: source .venv/bin/activate
Resolved 24 packages in 648ms
Downloading setuptools (1.2MiB)
Downloading nvidia-cuda-cupti-cu12 (13.2MiB)
Downloading torch (731.1MiB)
Downloading nvidia-nvjitlink-cu12 (20.1MiB)
Downloading nvidia-cufft-cu12 (201.7MiB)
Downloading nvidia-cuda-nvrtc-cu12 (23.5MiB)
Downloading nvidia-curand-cu12 (53.7MiB)
Downloading nvidia-nccl-cu12 (179.9MiB)
Downloading nvidia-cudnn-cu12 (634.0MiB)
Downloading nvidia-cublas-cu12 (346.6MiB)
Downloading sympy (5.9MiB)
Downloading nvidia-cusparse-cu12 (197.8MiB)
Downloading nvidia-cusparselt-cu12 (143.1MiB)
Downloading networkx (1.6MiB)
Downloading nvidia-cusolver-cu12 (122.0MiB)
Downloading triton (241.4MiB)
Downloaded setuptools
Downloaded networkx
Downloaded sympy
Downloaded nvidia-cuda-cupti-cu12
Downloaded nvidia-nvjitlink-cu12
Downloaded nvidia-cuda-nvrtc-cu12
Downloaded nvidia-curand-cu12
[...]
```
