Configure ruff in pyproject.toml and apply its fixes: modern annotations
(X | None, builtin generics, collections.abc), sorted imports, explicit
stacklevel in test warnings.
Configure pytest in pyproject.toml to import the repo copy, add a conftest that keeps tests out of the journal and desktop notifications, and test reading the config file and expanding paths.
Unencrypted ed25519 and ECDSA keys crashed with an uncaught
SSHException, and the DSA fallback raised NameError since paramiko 4
removed DSSKey. Load the key with paramiko.PKey.from_path instead,
ask for the passphrase only when the key is encrypted, and log an
error instead of crashing when the key can't be loaded.
Require paramiko >= 3.2 for PKey.from_path.
Fuxino
