fix(ci): use nixos-stable

ci.nix

@@ -3,7 +3,7 @@
   system,
   name,
 }: let
-  inherit (inputs) nixpkgs;
+  nixpkgs = inputs.nixos-stable;
   pkgs = nixpkgs.legacyPackages.${system};
   ensureFiles = paths:
     pkgs.runCommand "directory" {} ''
@@ -23,6 +23,13 @@
       "nixos-config=${toString ./.}/systems/${name}/configuration.nix"
       "system-secrets=${systemSecrets}"
       "secrets=${sharedSecrets}"
+      "nixpkgs=${
+        toString (
+          if name == "kabsa" || name == "manakish"
+          then inputs.nixos-unstable
+          else inputs.nixos-stable
+        )
+      }"
     ]
     ++ nixpkgs.lib.mapAttrsToList (name: value: "${name}=${value}") inputs);
   # cd ~/.password-store/shared && find * -type f | sed 's/.gpg$//'