Adds a feature page covering the rolling window, what counts, the MB/GB
estimate and the Docker/CLI keys, plus a one-line pointer from getting started
where a new user with a large Plus library clicks Begin Book Backups.
Scripts/seed-download-history.cs seeds fake completed downloads so the limit
can be exercised without downloading, including dating rows just under 24 hours
old to turn the multi-day pause-and-resume behavior into a one minute test.
Also shortens the queue status text: the process queue column clips rather than
wrapping, so the resume time was being cut off.
Co-authored-by: rmcrackan <rmcrackan@gmail.com>
Avalonia and WinForms both get a Daily download limit group on the
Download/Decrypt tab: scope drop-down, and when a limit is chosen a quantity
spinner (minimum 1, no practical maximum) plus a Books/MB/GB unit, with the
MB/GB approximation note shown only for those units.
A license denial that looks like Audible throttling now suggests turning the
limit on, quoting the real number of downloads Libation recorded in the last 24
hours. Audible reports no distinct throttling reason, so the suggestion stays
silent unless that record makes throttling plausible.
Co-authored-by: rmcrackan <rmcrackan@gmail.com>
