feat(portal): proxy Gitea SSH through HAProxy

- expose Gitea SSH through Portal on port 2223
- advertise the correct Gitea SSH user and domain
- add the Gitea host to Richie’s SSH config
- correct the local ACME challenge backend port

users/richie/home/ssh_config.nix

@@ -49,6 +49,12 @@
         IdentityFile = "~/.ssh/id_ed25519";
         Port = 278;
       };
+      "gitea.tmmworkshop.com" = {
+        HostName = "gitea.tmmworkshop.com";
+        User = "gitea";
+        IdentityFile = "~/.ssh/id_ed25519";
+        Port = 2223;
+      };
     };
   };
 }