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/home/hyprland/binds.nix

@@ -15,7 +15,7 @@
     "SUPER, G, exec, affinity-v3 #\"Graphics editor\""
     "SUPER, I, exec, iotas #\"Note-taking app\""
     "SUPER, J, exec, Jan #\"Local AI chat interface\""
-    "SUPER, K, exec, galculator #\"Scientific calculator\""
+    "SUPER, K, exec, gnome-calculator #\"Scientific calculator\""
     "SUPER, L, exec, logseq #\"Knowledge management tool\""
     "SUPER, M, exec, plexamp #\"Music player for Plex\""
     "SUPER, N, exec, dex ${desktopEntriesPath}/garandcloud.desktop #\"GarandCloud client\""

modules/home/hyprland/windowrules.nix

@@ -41,6 +41,7 @@ _: {
     "center on, match:class pavucontrol|org\.pulseaudio\.pavucontrol|com\.saivert\.pwvucontrol"
     "center on, match:class [Tt]hunar, match:title negative:.*[Tt]hunar.*"
     "center on, match:title Authentication Required"
+    "center on, match:class org\.gnome\.Calculator"
 
     # Idle inhibit rules
     "idle_inhibit fullscreen, match:class .*"
@@ -61,11 +62,13 @@ _: {
     "float on, match:initial_title Add Folder to Workspace"
     "float on, match:initial_title Open Files"
     "float on, match:initial_title wants to save"
+    "float on, match:class org\.gnome\.Calculator"
 
     # Size rules
     "size 70% 60%, match:initial_title Open Files"
     "size 70% 60%, match:initial_title Add Folder to Workspace"
     "size 70% 70%, match:tag settings*"
+    "size 360 616, match:class org\.gnome\.Calculator"
 
     # Tile rules
     "tile on, match:class affinity\.exe"
@@ -84,6 +87,7 @@ _: {
     "opacity 0.8 0.7, match:class gedit|org\.gnome\.TextEditor|mousepad"
     "opacity 0.9 0.8, match:class seahorse # gnome-keyring gui"
     "opacity 0.95 0.75, match:title Picture-in-Picture"
+    "opacity 0.9 0.8, match:class org\.gnome\.Calculator"
 
     # Picture-in-Picture specific rules
     "pin on, match:title Picture-in-Picture"