refactor: use overlays for my custom packages

apps/default.nix

@@ -1,8 +1,4 @@
-{
-  pkgs,
-  self,
-  ...
-}: let
+{pkgs, ...}: let
   inherit (pkgs.lib) getExe mapAttrs;
 
   mkApp = pkg: {
@@ -10,4 +6,4 @@
     type = "app";
   };
 in
-  mapAttrs (n: v: mkApp v) self.appsPackages.${pkgs.system}
+  mapAttrs (n: v: mkApp v) pkgs.appsPackages

apps/packages.nix

@@ -1,17 +1,15 @@
-{
-  inputs,
-  pkgs,
-  ...
-}: let
-  inherit (pkgs.lib) listToAttrs nameValuePair;
+{inputs, ...}: (final: prev: {
+  appsPackages = let
+    inherit (final.lib) listToAttrs nameValuePair;
 
-  buildApp = attrs: (pkgs.callPackage ./buildApp.nix ({} // inputs // attrs));
-  callPackage = file: pkgs.callPackage file ({inherit buildApp;} // inputs);
-in
-  listToAttrs (map (x: nameValuePair x (callPackage ./${x})) [
-    "extract-subs"
-    "gen-docs"
-    "mc-mods"
-    "pin-inputs"
-    "update-sources"
-  ])
+    buildApp = attrs: (final.callPackage ./buildApp.nix ({} // inputs // attrs));
+    callPackage = file: final.callPackage file ({inherit buildApp;} // inputs);
+  in
+    listToAttrs (map (x: nameValuePair x (callPackage ./${x})) [
+      "extract-subs"
+      "gen-docs"
+      "mc-mods"
+      "pin-inputs"
+      "update-sources"
+    ]);
+})