fix all the issues with persistence, and change GLaDOS to btrfs as an experiment

nixos/hosts/GLaDOS/configuration.nix

@@ -75,8 +75,36 @@
     #   };
     # };
   };
-
   boot = {
+    # Nuke root AND home subvolumes on every boot
+    initrd.systemd.services.wipe-my-fs = {
+      requires = ["dev-mapper-nvme_crypted.device"];
+      after = ["dev-mapper-nvme_crypted.device"];
+      wantedBy = ["initrd.target"];
+      script = ''
+        mkdir -p /btrfs_tmp
+          mount /dev/mapper/cryptroot /btrfs_tmp
+
+          delete_subvolume_recursively() {
+              IFS=$'\n'
+              for i in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
+                  delete_subvolume_recursively "/btrfs_tmp/$i"
+              done
+              btrfs subvolume delete "$1"
+          }
+
+          # Nuke and recreate root
+          delete_subvolume_recursively /btrfs_tmp/root
+          btrfs subvolume create /btrfs_tmp/root
+
+          # Nuke and recreate home (wipes /home — but we restore via impermanence)
+          delete_subvolume_recursively /btrfs_tmp/home
+          btrfs subvolume create /btrfs_tmp/home
+
+          umount /btrfs_tmp
+      '';
+    };
+
     loader.systemd-boot.enable = false;
     initrd.systemd.enable = true;
     kernelPackages = pkgs.linuxPackages_latest;
@@ -89,9 +117,6 @@
       pkiBundle = "/var/lib/sbctl";
     };
     extraModprobeConfig = ''
-      #fix for https://gitlab.freedesktop.org/drm/amd/-/issues/4141
-      amdgpu.runpm=0
-      amdgpu.dcdebugmask=0x10
     '';
   };