Add firefox, fix ssh config, flake update

modules/hm/ssh.nix

@@ -8,7 +8,7 @@
           user = "admin";
           hostname = "192.168.1.1";
           port = 2222;
-          controlPersist = "10m";
+          controlPersist = "no";
           addKeysToAgent = "9h";
           compression = false;
 
@@ -17,8 +17,15 @@
           serverAliveCountMax = 3;
           hashKnownHosts = false;
           userKnownHostsFile = "~/.ssh/known_hosts";
-          controlMaster = "auto";
-          controlPath = "~/.ssh/master-%r@%n:%p";
+          controlMaster = "no";
+          controlPath = "none";
+
+          extraOptions = {
+            KexAlgorithms = "curve25519-sha256@libssh.org,diffie-hellman-group14-sha256";
+            WarnWeakCrypto = "no";
+            ServerAliveInterval = "30";
+            ServerAliveCountMax = "4";
+          };
         };
         "aur" = {
           hostname = "aur.archlinux.org";