refactor: simplify host composition and shared feature config

modules/hosts/zenith/default.nix

@@ -31,8 +31,6 @@ in
     };
 
     sourceControl.users = {
-      kiri.personal.publicKey = "";
-
       ergon = {
         personal.publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPdR3KP2U84i7f7MlRqcML/3YyMw8JL3hdm637SkMUwO ergon@zenith#personal";
         work.publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIIHJz5uHKm0/TiMNh/cmzrODHNZ8NgEEZe+47XnJwQGk ergon@zenith#work";
@@ -40,7 +38,7 @@ in
     };
 
     users = {
-      kiri = {
+      kiri = metaLib.mkHostUser {
         account = metaLib.users.kiri;
         needsPassword = true;
         homeImports = [
@@ -51,7 +49,7 @@ in
         ];
       };
 
-      ergon = {
+      ergon = metaLib.mkHostUser {
         account = metaLib.users.ergon;
         needsPassword = true;
         homeImports = [
@@ -63,6 +61,7 @@ in
 
     imports = [
       nixosModules.workstation-base
+      nixosModules.qbittorrent-client
       nixosModules.laptop-power
       {
         hardware.enableRedistributableFirmware = true;