feat: remove attic, it works not well

home/base/core/core.nix

@@ -1,6 +1,5 @@
 {
   pkgs,
-  attic,
   nur-ryan4yin,
   ...
 }: {
@@ -52,8 +51,6 @@
     # productivity
     caddy # A webserver with automatic HTTPS via Let's Encrypt(replacement of nginx)
     croc # File transfer between computers securely and easily
-    # self-hosted nix cache server
-    attic.packages.${pkgs.system}.attic-client
     ncdu # analyzer your disk usage Interactively, via TUI(replacement of `du`)
   ];