Adds onion map (#4057)

If this PR fixes an issue, link it below. If not, delete these two
lines.
Resolves #4055 

## Description:

Adds a 512*512 onion map with 3 nations (Leafer Confederation, Outer
Enclave and Inner Tribe)

<img width="128" height="128" alt="thumbnail"
src="https://github.com/user-attachments/assets/8d97d8dc-6286-4e79-a459-767c936d49ec"
/>


## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

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

tktk1234567

map-generator/assets/maps/onion/info.json

@@ -0,0 +1,20 @@
+{
+  "name": "onion",
+  "nations": [
+    {
+      "coordinates": [51, 188],
+      "name": "Leafer Confederation",
+      "flag": ""
+    },
+    {
+      "coordinates": [252, 199],
+      "name": "Outer Enclave",
+      "flag": ""
+    },
+    {
+      "coordinates": [252, 233],
+      "name": "Inner Tribe",
+      "flag": ""
+    }
+  ]
+}

map-generator/main.go

@@ -83,6 +83,7 @@ var maps = []struct {
 	{Name: "northamerica"},
 	{Name: "northwestpassage"},
 	{Name: "oceania"},
+	{Name: "onion"},
 	{Name: "pangaea"},
 	{Name: "passage"},
 	{Name: "pluto"},

resources/lang/en.json

@@ -605,6 +605,7 @@
     "korea": "Korea",
     "indiansubcontinent": "Indian Subcontinent",
     "balkans": "Balkans",
+    "onion": "Onion",
     "yellowsea": "Yellow Sea",
     "labyrinth": "Labyrinth"
   },

resources/maps/onion/manifest.json

@@ -0,0 +1,35 @@
+{
+  "map": {
+    "height": 512,
+    "num_land_tiles": 210555,
+    "width": 512
+  },
+  "map16x": {
+    "height": 128,
+    "num_land_tiles": 12499,
+    "width": 128
+  },
+  "map4x": {
+    "height": 256,
+    "num_land_tiles": 51713,
+    "width": 256
+  },
+  "name": "onion",
+  "nations": [
+    {
+      "coordinates": [51, 188],
+      "flag": "",
+      "name": "Leafer Confederation"
+    },
+    {
+      "coordinates": [252, 199],
+      "flag": "",
+      "name": "Outer Enclave"
+    },
+    {
+      "coordinates": [252, 233],
+      "flag": "",
+      "name": "Inner Tribe"
+    }
+  ]
+}

src/core/game/Game.ts

@@ -179,6 +179,7 @@ export enum GameMapType {
   Balkans = "Balkans",
   YellowSea = "Yellow Sea",
   Labyrinth = "Labyrinth",
+  Onion = "Onion",
 }
 
 export type GameMapName = keyof typeof GameMapType;
@@ -272,6 +273,7 @@ export const mapCategories: Record<string, GameMapType[]> = {
     GameMapType.DidierFrance,
     GameMapType.Labyrinth,
     GameMapType.Sierpinski,
+    GameMapType.Onion,
   ],
   tournament: [
     GameMapType.Tourney1,

src/server/MapPlaylist.ts

@@ -107,6 +107,7 @@ const FREQUENCY: Partial<Record<GameMapName, number>> = {
   YellowSea: 5,
   Yenisei: 6,
   Labyrinth: 6,
+  Onion: 2,
 };
 
 const TEAM_WEIGHTS: { config: TeamCountConfig; weight: number }[] = [