SecureShell Go 1.4.2

1.4.1 made "no system keyring" stop being a dead end, but it did so by
asking the user to choose how their credentials should be protected —
a mode setting, a dialog, a settings row and a first-run notice, all in
the way of simply saving a server. This release deletes that entirely.

One rule instead of a menu

Credentials go to the system keyring when it answers. When it does not,
they are encrypted into the app's own private file — automatically,
silently, without asking. There is no mode to pick and nothing to
configure, and there is still nowhere a secret is written unprotected.

Vaults written by 1.4.1 continue to open. Around 700 lines of the
machinery that existed only to let the user state which store held the
key are gone.

Saving is faster where it was slowest

Device encryption no longer runs Argon2id. That function exists to make
guessing a human-chosen password expensive; it was being applied to a
256-bit random key, where it protects nothing and cost roughly a second
on the first save and again on every app start. It landed on exactly the
machines the fallback exists for — snap installs without the keyring
interface connected, headless boxes, minimal desktops.

The key file now holds the vault key directly. The vault records which
of the two wrapping schemes it used in a byte covered by the
authentication tag, so an old file is still read as an old file and a
relabelled one is rejected.

Fixes

• A server with the sftp subsystem disabled no longer hangs the file
  browser. The SSH library returns a client without waiting to learn
  whether the server agreed to start the subsystem, so a refusal
  surfaced only on the first request — which never completed and never
  failed. The subsystem is now confirmed before the panel waits on it.

• Disconnecting the last session returns to the host list at once
  rather than showing an empty window until the connection has finished
  closing — worst against a server that had already stopped answering.

• The host actions menu and the copy-to-server picker scroll when
  they are taller than the window, instead of overflowing and hiding
  their last entries.

• A snap install is told how to fix its keyring access again. The
  host editor was picking a generic sentence and discarding the one the
  app had composed, which for a snap is the exact command to run:

  sudo snap connect secureshellgo:password-manager-service