fix: use lib in spore backup module to satisfy statix and NixOS args

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: stackptr

hosts/spore/backup.nix

@@ -1,6 +1,6 @@
-{_}: {
+{lib, ...}: {
   rc.backup = {
-    enable = true;
+    enable = lib.mkForce true;
     paths = [];
   };
 }