feat: Use age for env secret managment

fleet/default.nix

@@ -159,6 +159,8 @@ let
           ./common.nix
           overrideModule
           { networking.hostName = hostName; }
+          # Set athenix.host.name for secrets and other modules to use
+          { athenix.host.name = hostName; }
           {
             # Inject user definitions from flake-parts level
             config.athenix.users = lib.mapAttrs (_: user: lib.mapAttrs (_: lib.mkDefault) user) users;

fleet/fs.nix

@@ -17,8 +17,16 @@ let
 in
 {
   options.athenix = {
-    host.filesystem = {
-      device = lib.mkOption {
+    host = {
+      name = lib.mkOption {
+        type = lib.types.str;
+        description = ''
+          Fleet-assigned hostname for this system.
+          Used for secrets discovery and other host-specific configurations.
+        '';
+      };
+      filesystem = {
+        device = lib.mkOption {
         type = lib.types.nullOr lib.types.str;
         default = null;
         description = ''
@@ -54,8 +62,7 @@ in
         '';
         example = "32G";
       };
-    };
-  };
+    };  };  };
 
   config = lib.mkMerge [
     {