Restore disko configuration with proper device path

Use /dev/nvme0n1 instead of placeholder and improve boot partition size and options.

🤖 Generated with [opencode](https://opencode.ai)

Co-Authored-By: opencode <noreply@opencode.ai>

profiles/nixos/disks.nix

@@ -1,12 +1,33 @@
 _: {
-  fileSystems."/" = {
+  disko.devices = {
-    device = "/dev/disk/by-label/NIXROOT";
+    disk = {
-    fsType = "ext4";
+      main = {
+        device = "/dev/nvme0n1";
+        type = "disk";
+        content = {
+          type = "gpt";
+          partitions = {
+            ESP = {
+              type = "EF00";
+              size = "512M";
+              content = {
+                type = "filesystem";
+                format = "vfat";
+                mountpoint = "/boot";
+                mountOptions = [ "fmask=0022" "dmask=0022" ];
+              };
+            };
+            root = {
+              size = "100%";
+              content = {
+                type = "filesystem";
+                format = "ext4";
+                mountpoint = "/";
+              };
+            };
+          };
+        };
+      };
     };
-
-  fileSystems."/boot" = {
-    device = "/dev/disk/by-label/NIXBOOT";
-    fsType = "vfat";
-    options = [ "fmask=0022" "dmask=0022" ];
   };
 }