Fix: SSH-Verbindung scheiterte an Key-Exchange-Aushandlung mit RouterOS

RouterOS' SSH-Server bietet typischerweise nur ältere Algorithmen an
(diffie-hellman-group14-sha1, RSA-Hostkeys), die in Citadels
Standard-Algorithmenliste fehlen -> keyExchangeNegotiationFailure beim
Verbindungstest gegen echtes Gerät. Citadels vorgefertigtes
SSHAlgorithms.all-Preset aktiviert diese Legacy-Algorithmen.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HReLXMbmPvtQ23p1iWiJNW

RouterOSAssistant/Core/Networking/SSHTransport.swift

@@ -24,7 +24,11 @@ final class SSHTransport: RouterOSTransport {
                 port: credentials.sshPort,
                 authenticationMethod: .passwordBased(username: credentials.username, password: credentials.password),
                 hostKeyValidator: .acceptAnything(),
-                reconnect: .never
+                reconnect: .never,
+                // RouterOS' SSH server typically only offers legacy algorithms
+                // (diffie-hellman-group14-sha1 key exchange, RSA host keys) that
+                // Citadel's defaults don't include — `.all` adds them.
+                algorithms: .all
             )
         } catch {
             // NIOSSHError's `.localizedDescription` is a useless generic NSError-bridged string