refactor: rename some flake attr directories

nixFastChecks/packages/default.nix

@@ -0,0 +1,18 @@
+{
+  pkgs,
+  self,
+}: let
+  inherit (pkgs.lib) elem filterAttrs hasAttr mapAttrs' nameValuePair;
+
+  packages =
+    filterAttrs (
+      _: v:
+        !(hasAttr "platforms" v.meta)
+        || elem pkgs.system v.meta.platforms
+    )
+    self.packages.${pkgs.system};
+in
+  mapAttrs'
+  (name: pkg:
+    nameValuePair "pkg_${name}" pkg)
+  packages