refactor: simplify host setup

modules/system/networking.nix

@@ -1,5 +1,5 @@
-{hostname, ...}: {
+{config, ...}: {
   networking = {
-    hostName = hostname;
+    hostName = config.fireproof.hostname;
   };
 }

modules/system/ssh.nix

@@ -1,11 +1,11 @@
 {
   config,
   pkgs,
-  username,
-  hostname,
   lib,
   ...
 }: let
+  inherit (config.fireproof) username;
+  inherit (config.fireproof) hostname;
   # Load all public keys from ../../secrets/hosts/*/id_ed25519.pub
   allHosts = lib.attrNames (lib.filterAttrs (_: type: type == "directory") (builtins.readDir ../../secrets/hosts));
   publicKeys = map (x: builtins.readFile (../../secrets/hosts + ("/" + x) + "/id_ed25519.pub")) allHosts;

modules/system/user.nix

@@ -1,8 +1,5 @@
-{
-  username,
-  config,
-  ...
-}: let
+{config, ...}: let
+  inherit (config.fireproof) username;
   inherit (config.age) secrets;
 in {
   config = {