chore: replace impermanence with preservation (#201)

hosts/idols-ai/hardware-configuration.nix

@@ -96,7 +96,7 @@
     device = "/dev/disk/by-uuid/1167076c-dee1-486c-83c1-4b1af37555cd";
     fsType = "btrfs";
     options = ["subvol=@persistent" "compress-force=zstd:1"];
-    # impermanence's data is required for booting.
+    # preservation's data is required for booting.
     neededForBoot = true;
   };
 

hosts/idols-ai/preservation.nix

@@ -31,7 +31,7 @@ in {
   #
   #  See also https://grahamc.com/blog/erase-your-darlings/
 
-  # NOTE: impermanence only mounts the directory/file list below to /persistent
+  # NOTE: preservation only mounts the directory/file list below to /persistent
   # If the directory/file already exists in the root filesystem you should
   # move those files/directories to /persistent first!
   preservation.preserveAt."/persistent" = {