v0.84.0: Page-by-page downloads

Downloads you can watch page by page, double pages that line up, and gallery chapters. All three are pull requests
from @globalteddy (#296,
#295, #294), merged
with his own commits. Thank you.

• Page-by-page download progress (#296). A chapter coming in
  shows its pages and the time left under the series in Library → Downloads and on the series page (34/78 pages ·
  about 40 s left). The time left covers the chapters still to come, and the Library ring moves while a long chapter
  comes in, not only when it lands. The time is measured by the server, so a device whose clock is off still reads it
  right.
• Shift pairs by one page (#295). In Double spread, the
  reader keeps a chapter's first page alone as a cover. For a title whose chapters start on a story page, Shift pairs
  by one page in Reader settings pairs pages 1–2, 3–4 and so on. It is remembered for that title, and the page you
  are reading stays in view when you switch it.
• Gallery chapters (#294). An extension that lists a gallery as
  one chapter with no number made the series look empty. That chapter now counts as chapter 1, and an 18+ extension
  listing only unnumbered parts gets them numbered in posting order. Chapters that have numbers are read as before.

Upgrading

• Nothing to do. The database has no change.

Uchiyomi Desktop (beta): downloads

Uchiyomi as a program on your own computer, for Windows and Mac. On first launch it asks how you want to
use it: on this computer (the whole app, with the library in a folder on your PC and no Docker or
server to run) or connected to your own Uchiyomi server (a window onto the server you already run).

Your computer	Download
Windows (x64)	Uchiyomi-Setup-0.84.0.exe
Mac with Apple silicon (M1 or newer)	Uchiyomi-0.84.0-arm64.dmg
Mac with an Intel processor	Uchiyomi-0.84.0-x64.dmg

Only those three are for you: the .zip, .blockmap and latest*.yml files are what the app's own updater
reads. The same installers are also here under names without a version (Uchiyomi-Setup.exe,
Uchiyomi-mac-arm64.dmg, Uchiyomi-mac-x64.dmg), which always lead to the newest release.

The app is not signed yet, so the first launch takes one extra step:

• Windows: "Windows protected your PC" appears once. Choose More info, then Run anyway. A PC
  with Smart App Control turned on blocks unsigned apps with no way past it; use the Docker install there.
• macOS: open the dmg and drag Uchiyomi to Applications. The first time you open it, macOS refuses;
  go to System Settings → Privacy & Security and choose Open Anyway.

Windows installs updates by itself. A Mac cannot update an unsigned app, so there a new version is a new
download; the menu-bar icon and Admin → Health say when one is out.

Step by step, with pictures -- which file, the first launch on each system, the two ways to use it, adding
sources, updates, backups, where files live and uninstalling:
the desktop guide.