Server/ssh: add ssh host key

roles/server/ssh.nix

@@ -1,4 +1,23 @@
-{...}: {
+{
+  flakeSelf,
+  config,
+  ...
+}: let
+  hostSecrets = "${flakeSelf.inputs.secrets}/" + config.networking.hostName + "/";
+  hostKeyPath = "/etc/ssh/everest_host_key";
+in {
+  age.secrets = {
+    everest-host-key = {
+      file = hostSecrets + "host-private-key.age";
+      path = hostKeyPath;
+      mode = "0400";
+    };
+    "everest-host-key.pub" = {
+      file = hostSecrets + "host-public-key.age";
+      path = hostKeyPath + ".pub";
+    };
+  };
+
   services.openssh = {
     enable = true;
     settings = {
@@ -6,6 +25,13 @@
       PermitRootLogin = "no";
       PasswordAuthentication = false;
     };
+    hostKeys = [
+      {
+        path = hostKeyPath;
+        type = "ed25519";
+        comment = "Everest host key";
+      }
+    ];
     startWhenNeeded = true;
   };
 }