refactor: add SystemStats singleton + nova-stats daemon for cpu/mem polling

nix/hm-module.nix

@@ -202,7 +202,8 @@ in
       pkgs.nerd-fonts.symbols-only
     ]
     ++ lib.optional cfg.modules.weather.enable pkgs.wttrbar
-    ++ lib.optional cfg.modules.mpris.enable pkgs.cava;
+    ++ lib.optional cfg.modules.mpris.enable pkgs.cava
+    ++ lib.optional cfg.modules.disk.enable pkgs.coreutils;
 
     xdg.configFile."nova-shell/modules.json".source =
       (pkgs.formats.json { }).generate "nova-shell-modules.json"

nix/package.nix

@@ -4,6 +4,7 @@
   makeWrapper,
   quickshell,
   qt6,
+  nova-stats,
 }:
 stdenvNoCC.mkDerivation {
   pname = "nova-shell";
@@ -32,7 +33,8 @@ stdenvNoCC.mkDerivation {
 
     mkdir -p $out/bin
     makeWrapper ${lib.getExe quickshell} $out/bin/nova-shell \
-      --add-flags "-p $out/share/nova-shell/shell.qml"
+      --add-flags "-p $out/share/nova-shell/shell.qml" \
+      --prefix PATH : ${lib.makeBinPath [ nova-stats ]}
 
     runHook postInstall
   '';

nix/stats-daemon.nix

@@ -0,0 +1,12 @@
+{ lib, rustPlatform }:
+rustPlatform.buildRustPackage {
+  pname = "nova-stats";
+  version = "0.1.0";
+  src = lib.cleanSource ../stats-daemon;
+  cargoLock.lockFile = ../stats-daemon/Cargo.lock;
+  meta = {
+    description = "System stats daemon for nova-shell";
+    mainProgram = "nova-stats";
+    platforms = lib.platforms.linux;
+  };
+}