Ferry 0.0.2

A site's check for a person is shown to the person. Some sites put a check before their pages that only a person in a
browser can pass: a picture of characters to type, say. A plugin can now tell Ferry so, and never answers one itself.

• On the Browser page, the site's own page opens in a window, reached through your server, so the site sees the address
  its pages are then read from. You pass the check; Ferry types nothing. The window closes when the site has let you
  through, and what you asked for is read again.
• One window at a time. A check you close without passing is left alone for half a minute.
• Away from the Browser page (a watched album, a file in the queue) nothing is shown, and the failure says what to do.
• It needs your server's SSH to pass connections on (AllowTcpForwarding, on unless a host turned it off) and Microsoft
  Edge WebView2, which comes with Windows 11.
• For plugin writers: StageException.Check and ICheckedPlugin, in docs/writing-plugins.md. The contract's number
  stays 1, so packages made for 0.0.1 still load.

The window and the tunnel behind it were built and tested in parts, and have not yet been used against a real site.

Checksums: SHA256SUMS.txt. The app updates itself; the .tar.gz files are the agent for a server, which the app fetches when it needs one.