Batch Issue: feedback from DWEA demo

Feedback received from Caleb's DWEA demo as a parent issue and detailed feedback as sub-issues:

Hi Folks, I wanted to pass along some feedback that came up during the demo at DWEA this week of the existing windwatts site which we might consider incorporating into the new site (at some point -- maybe not immediately).
We need a way to change units and ideally default to imperial units (i.e., mph for windspeeds, with metric as a secondary option). This seems like something we may want to do now.
They would like the option see multiple heights of data at once, or perhaps compare heights. In the current tool you pick the height first, so this would be a change to the UX
They are interested in a PDF or an ability to easily print the wind watts output (neat idea!)
Lindsay and I had a discussion about leading with the ERA5 data and having the WTK-LED data as a secondary option, so effectively switching the order of which results we display first. We should confirm this with Dmitry, but I think it could be an important option to consider.
There are some requests for documentation, e.g., better/more accessible explanation of the wind models that are included, the low/mod/high categories etc.
We also had multiple people ask about the API interface, so it's good to hear that this is still an important feature for us to support - i.e., for users that want programmatic access to screen multiple sites at once.

No files, tests, or entry points are identified. Treat this as a parent issue and first split the unit-selection, multi-height comparison, PDF or print output, data ordering, documentation, and API requests into discrete issues. Each child issue should define its entry point, expected result, and validation steps.