Add category to singleplayer (#449)

## Description:
Just simply adds categories to the single player menu
![Screenshot 2025-04-11 at 05 40
49](https://github.com/user-attachments/assets/e6811b69-5abf-427f-9989-55f4538b034f)

Fixes #453 

## Please complete the following:

- [X] I have added screenshots for all UI updates
- [X] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [X] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

## Please put your Discord username so you can be contacted if a bug or
regression is found:

lunhuiyan1718

resources/lang/en.json

@@ -123,6 +123,11 @@
     "knownworld": "Known World",
     "faroeislands": "Faroe Islands"
   },
+  "map_categories": {
+    "continental": "Continental",
+    "regional": "Regional",
+    "fantasy": "Other"
+  },
   "private_lobby": {
     "title": "Join Private Lobby",
     "enter_id": "Enter Lobby ID",