Switch from Evolution to GNOME Calendar module

- Enable `calendar.enable` instead of `evolution.enable` in all host
  system‑modules files.
- Add `modules/core/calendar.nix` defining the calendar option and
  installing GNOME Calendar and Contacts.
- Remove the deprecated `modules/core/evolution.nix` and update
  `core/default.nix` imports accordingly.
- Include the GNOME package set via `./gnome.nix` in
  `modules/core/packages/default.nix`.

modules/core/calendar.nix

@@ -0,0 +1,16 @@
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}: {
+  options.calendar.enable = lib.mkEnableOption "Enable GNOME Calendar";
+
+  config = {
+    services.gnome.evolution-data-server.enable = lib.mkIf config.calendar.enable true;
+    environment.systemPackages = lib.mkIf config.calendar.enable (with pkgs; [
+      gnome-calendar
+      gnome-contacts
+    ]);
+  };
+}

modules/core/default.nix

@@ -2,8 +2,8 @@
   imports = [
     ./packages
     ./boot.nix
+    ./calendar.nix
     ./docker.nix
-    ./evolution.nix
     ./flatpak.nix
     ./fonts.nix
     ./garandos-tui.nix

modules/core/evolution.nix

@@ -1,12 +0,0 @@
-{
-  lib,
-  config,
-  ...
-}: {
-  options.evolution.enable = lib.mkEnableOption "Enable Evolution";
-
-  config = {
-    programs.evolution.enable = lib.mkIf config.evolution.enable true;
-    services.gnome.evolution-data-server.enable = lib.mkIf config.evolution.enable true;
-  };
-}

modules/core/packages/packages.nix

@@ -16,7 +16,7 @@
   packages = with pkgs; {
     bitwarden = bitwarden-desktop;
     eddieAirVPN = eddie;
-    galculator = galculator;
+    gnomeCalculator = gnome-calculator;
     gedit = gedit;
     iotas = iotas;
     logseq = logseq;