Add ZRAM module and enable it in core defaults

modules/core/default.nix

@@ -26,6 +26,7 @@
     ./virtualbox.nix
     ./xdg.nix
     ./xserver.nix
+    ./zram.nix
     inputs.stylix.nixosModules.stylix
   ];
 }

modules/core/zram.nix

@@ -0,0 +1,32 @@
+{pkgs, ...}: {
+  zramSwap = {
+    enable = true;
+    priority = 5;
+    memoryMax = 16 * 1024 * 1024 * 1024;
+    algorithm = "zstd";
+    swapDevices = 1;
+    memoryPercent = 50;
+  };
+  boot = {
+    kernelParams = [
+      "zswap.enabled=1" # enables zswap
+      "zswap.compressor=zstd" # compression algorithm
+      "zswap.max_pool_percent=20" # maximum percentage of RAM that zswap is allowed to use
+      "zswap.shrinker_enabled=1" # whether to shrink the pool proactively on high memory pressure
+    ];
+    tmp = {
+      useZram = true;
+      zramSettings = {
+        compression-algorithm = "zstd";
+        zram-size = "ram * 0.5";
+        fs-type = "ext4";
+        options = "X-mount.mode=1777,discard";
+      };
+    };
+  };
+  services.zram-generator = {
+    enable = true;
+    package = pkgs.zram-generator;
+    settings = {};
+  };
+}