feat: support jump host ports in SSH menu

Allow jump host definitions to include an explicit port in the form user@host:port.
Default to port 22 when no port is provided and update the sample config and docs accordingly.

sample-config/global.yaml

@@ -4,3 +4,5 @@ ssh:
   default_options: ""
   jump_hosts:
     office: "user@192.168.10.11"
+    dev: "user@192.168.10.11:2222"
+    backup: "admin@10.0.0.5:2200"