saturnus 0.4.0

saturnus 0.4.0 lets the emulator and saturnus tx share one live
calculator, adds four calculators (the HP 27S, 17BII, 17B and 28S), and
makes saturnus tx faster and easier to follow.

Get it

• On the web, nothing to install: the emulator at
  https://ractive.ch/saturnus/emulator/, saturnus tx at
  https://ractive.ch/saturnus/transfer/ (Chrome or Edge for a serial
  cable; every browser for the emulated calculator).
• The desktop apps: saturnus_0.4.0_… (the emulator, on Linux
  saturnus-app) and saturnus-tx_0.4.0_…: .dmg (macOS, Apple
  silicon, signed and notarised, or brew trust --cask ractive/tap/saturnus-app and brew trust --cask ractive/tap/saturnus-tx once, then brew install --cask ractive/tap/saturnus-app or ractive/tap/saturnus-tx), .msi or
  -setup.exe (Windows x86_64), .deb, .rpm or .AppImage (Linux
  x86_64). On Linux, add yourself to the dialout group to use a
  serial port.
• The command-line tools saturnus and satx: cargo install,
  Homebrew ractive/tap, Scoop ractive, or the archives and Linux
  packages below.
• Libraries on crates.io, all at 0.4.0: saturnus-core,
  saturnus-objects, saturnus-host, saturnus-drive, kermit-proto,
  xmodem-proto and satx-core. 0.4 changes some of their public
  types (the screen's width, new models and keys); CHANGELOG.md lists
  what to adapt.

One calculator for the emulator and saturnus tx

The emulated 48SX, 48GX or 49G that saturnus tx connects to is now the
emulator's own calculator, running. What you type in the emulator shows
up in saturnus tx at once, and what you copy in saturnus tx appears in
the emulator's memory and on its screen as it happens. Closing either
page leaves the other one running. Both pages must be the same version
("Reload the page" otherwise).

New calculators

• HP 27S, 17BII and 17B, and the HP 28S with its open clamshell
  and letter keyboard, each with a drawn skin. None of their ROMs was
  ever published: read the ROM out of your own calculator. They have no
  serial port, so saturnus tx does not offer them.
• Their self-tests, and the 42S's, now pass the ROM check.

Emulator

• Set the clock: one button sets the calculator to your computer's
  date and time, on every model that has a clock; optionally on every
  start.

saturnus tx

• Progress where you click: a preview shows what is being read, how
  much, and how long a slow cable will take.
• Show the cable: a console lists every packet on the link, in plain
  words, with errors in red.
• Open in the emulator opens the emulator on the calculator a pane
  shows.
• Files in this browser is the new name of the storage used where
  no folder can be chosen (Firefox, Safari), so nobody looks for it in
  Downloads.
• Faster emulated calculators: connected and listed in about 3 s
  instead of 11, and copies in seconds instead of minutes.
• File previews show programs and expressions with the 48SX's and
  48GX's command names.
• The graphics screen goes to the other pane like any variable.
• A calculator is no longer left waiting in "Awaiting Server Cmd.".

Fixes behind the scenes

• The test suites' emulator start-up no longer fails now and then on CI.

See CHANGELOG.md for the full list.

The Windows installers are not signed

SmartScreen says "Windows protected your PC": click "More info", then
"Run anyway".

ROMs are not included

saturnus ships no ROM. saturnus rom fetch --model <m>, the web page and
the app download the images hpcalc.org offers for use with emulators,
after asking. The ROMs of the 42S, 27S, 17BII, 17B and 28S were never
released: dump your own calculator (see the README).

Clean room and AI notice

saturnus is written from public hardware documentation and the observed
behaviour of the calculators' own ROMs, not from the source code of other
emulators, and contains no HP logos or wordmarks. Parts of the code were
generated by AI systems under human supervision; see AI_NOTICE. MIT
licence.