empty --password '' for ssh

Author: jquast

README.md

@@ -99,8 +99,8 @@ SSH server
 It is possible to serve the emulation through SSH. Clients with terminals supporting the [kitty keyboard protocol](https://sw.kovidgoyal.net/kitty/keyboard-protocol/) can send input directly without X11 forwarding. Otherwise, X11 forwarding (`ssh -X`) can be used as a fallback. Use `gambaterm-ssh --help` for more information. 24-bit color is always assumed over SSH. Audio is not available over SSH.
 
 ```shell
-$ gambaterm-ssh --password 123 myrom.gbc
-$ gambaterm-ssh --password 123 --bind 0.0.0.0 --port 8022 myrom.gbc  # Listen on all interfaces
+$ gambaterm-ssh --password '' myrom.gbc  # with no password (press return if prompted)
+$ gambaterm-ssh --password '' --bind 0.0.0.0 --port 8022 myrom.gbc  # Listen on all interfaces
 ```
 
 Connect with ssh client:

gambaterm/ssh.py

@@ -267,7 +267,9 @@ def session_requested(self) -> SSHServerProcess[str]:
         )
 
     def password_auth_supported(self) -> bool:
-        return bool(self._gambaterm_password)
+        # Allow empty string as a valid password (--password ''),
+        # only None (unset) disables password auth.
+        return self._gambaterm_password is not None
 
     def validate_password(self, username: str, password: str) -> bool:
         assert self._gambaterm_password is not None