saturnus 0.6.0

saturnus 0.6.0 makes the emulator and saturnus tx one app: a home page
with your calculators, and Calculator and Files side by side, on the web
and on the desktop.

Get it

• On the web, nothing to install: https://ractive.ch/saturnus/app/
  (Chrome or Edge for a serial cable; every browser for the emulated
  calculator). The old addresses /saturnus/emulator/ and
  /saturnus/transfer/ are gone; an app installed from them retires
  itself and opens the new one. Kept ROMs and saved states stay.
• The desktop app saturnus_0.6.0_… (on Linux saturnus-app):
  .dmg (macOS, Apple silicon, signed and notarised, or brew trust --cask ractive/tap/saturnus-app once, then brew install --cask ractive/tap/saturnus-app), .msi or -setup.exe (Windows x86_64),
  .deb, .rpm or .AppImage (Linux x86_64), with a -SHA256SUMS
  file beside them. On Linux, add yourself to the dialout group to use
  a serial port. The separate saturnus tx desktop app and its cask are
  gone: brew uninstall --cask saturnus-tx if you had it.
• 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 0.6.0, unchanged apart from the
  version.

One app

• A home page lists the calculators you kept, each with
  Calculator and Files, marks the running ones, and offers a new
  calculator or one on a cable.
• Calculator and Files are two views of one page: switching never
  reloads it or stops the calculator, and a transfer goes on whichever
  view is shown.
• On the desktop, Files works the calculator the app is running
  (through the native engine), a calculator on a serial cable, and the
  computer's folders, in the same window.

Smaller changes

• Files: .. goes up a folder; folders have a filled icon and
  semi-bold names; Settings works on the emulator's calculator; "Show
  the packets" (was "Show the cable"), hidden where there are none.
• One WebAssembly package for the whole web app.