refactor(flake): centralize custom packages

configs/nixos/modules/desktop/session/waybar.nix

@@ -30,32 +30,7 @@ in
 
     home-manager.users.${config.user.name}.programs.waybar = {
       enable = true;
-      # Waybar 0.15.0 sends old Hyprland workspace dispatch commands.
-      # Use the fix commit until a release includes upstream PR #5013.
-      package = pkgs.waybar.overrideAttrs {
-        src = pkgs.fetchFromGitHub {
-          owner = "Alexays";
-          repo = "Waybar";
-          rev = "05945748dccce28bf96d26d8f64a9e69a8dd49ba";
-          hash = "sha256-51R3mIt8cLNvh/X5qe9vOqeJCj0U9KRyemVE5y+OhiU=";
-        };
-
-        postUnpack =
-          let
-            libcava = pkgs.fetchFromGitHub {
-              owner = "LukashonakV";
-              repo = "cava";
-              tag = "0.10.7";
-              hash = "sha256-zkyj1vBzHtoypX4Bxdh1Vmwh967DKKxN751v79hzmgQ=";
-            };
-          in
-          ''
-            pushd "$sourceRoot"
-            cp -R --no-preserve=mode,ownership ${libcava} subprojects/cava-0.10.7
-            patchShebangs .
-            popd
-          '';
-      };
+      package = pkgs.alexion.waybar;
 
       # A user service bound to graphical-session.target, which uwsm activates,
       # so the bar comes up with the session and no compositor exec-once.

configs/nixos/modules/shell/pi/default.nix

@@ -12,18 +12,14 @@ let
   piDir = "${config.users.users.${user}.home}/.pi/agent";
 in
 {
-  options.modules.shell.pi = {
-    enable = lib.mkEnableOption "Pi, a terminal coding agent, configured through home-manager";
-  };
+  options.modules.shell.pi.enable =
+    lib.mkEnableOption "Pi, a terminal coding agent, configured through home-manager";
 
   config = lib.mkIf config.modules.shell.pi.enable {
     home-manager.users.${user} = {
       programs.pi-coding-agent = {
         enable = true;
-        package = pkgs.pi-coding-agent.overrideAttrs {
-          src = ../../../../../third_party/pi;
-          patches = [ ];
-        };
+        package = pkgs.alexion.pi-coding-agent;
 
         settings = {
           defaultProvider = "openai-codex";

src/dotfiles/default.nix

@@ -33,7 +33,12 @@ let
     repositoryModules = modules;
     root = root + "/guests";
   };
-  modules.imports = util.collectNixFiles (root + "/modules");
+  modules.imports = [
+    {
+      nixpkgs.overlays = [ self.overlays.custom ];
+    }
+  ]
+  ++ util.collectNixFiles (root + "/modules");
 
 in
 import ./hosts.nix {

src/flake/default.nix

@@ -6,6 +6,19 @@
   system,
 }:
 {
+  overlays.custom = final: _prev: {
+    alexion = import ./packages {
+      pkgs = final;
+      inherit root;
+    };
+  };
+
+  packages.${system} =
+    (import inputs.nixpkgs {
+      inherit system;
+      overlays = [ self.overlays.custom ];
+    }).alexion;
+
   nixosConfigurations = import ../dotfiles {
     inherit
       inputs

src/flake/packages/default.nix

@@ -0,0 +1,8 @@
+{ pkgs, root }:
+{
+  pi-coding-agent = pkgs.callPackage ./pi-coding-agent.nix {
+    inherit root;
+  };
+
+  waybar = pkgs.callPackage ./waybar.nix { };
+}

src/flake/packages/pi-coding-agent.nix

@@ -0,0 +1,8 @@
+{
+  pi-coding-agent,
+  root,
+}:
+pi-coding-agent.overrideAttrs {
+  src = root + "/third_party/pi";
+  patches = [ ];
+}

src/flake/packages/waybar.nix

@@ -0,0 +1,28 @@
+{
+  fetchFromGitHub,
+  waybar,
+}:
+waybar.overrideAttrs {
+  src = fetchFromGitHub {
+    owner = "Alexays";
+    repo = "Waybar";
+    rev = "05945748dccce28bf96d26d8f64a9e69a8dd49ba";
+    hash = "sha256-51R3mIt8cLNvh/X5qe9vOqeJCj0U9KRyemVE5y+OhiU=";
+  };
+
+  postUnpack =
+    let
+      libcava = fetchFromGitHub {
+        owner = "LukashonakV";
+        repo = "cava";
+        tag = "0.10.7";
+        hash = "sha256-zkyj1vBzHtoypX4Bxdh1Vmwh967DKKxN751v79hzmgQ=";
+      };
+    in
+    ''
+      pushd "$sourceRoot"
+      cp -R --no-preserve=mode,ownership ${libcava} subprojects/cava-0.10.7
+      patchShebangs .
+      popd
+    '';
+}