Added a public game modifier system 😮 For more variety (#2801)

## Description:

Added a public game modifier system. It causes that

5% of public games are played on the compact version of the map
10% of public games have "Random Spawn" activated

Percentages can easily get changed via `DefaultConfig`.
We can also easily add more modifiers.
Modifiers can stack, so in rare cases you will play on a compact map
with random spawn 😄
More variety!

### "Compact Map" modifier implementation

- With the "Compact Map" modifier the lobby max player count gets
reduced to 25% and only 25% of the regular bots and only 25% of the
regular nations will spawn (because the map has only 25% of its regular
size)
- In private lobbies and singleplayer the nation reduction happens too
(When "Compact Map" is enabled).

### Restrictions

- Duos/Trios/Quads team modes do not get Random Spawn (defeats the
purpose)
- Maps with smallest player count < 50 do not get Compact Map in team
games (not enough players after the reduction to 25%). I have calculated
all the possible max player counts.

### How it looks like

Random Spawn modifier:

<img width="528" height="183" alt="Screenshot 2026-01-06 194959"
src="https://github.com/user-attachments/assets/2f729da9-80c3-4548-8205-71129da2a76a"
/>

Very rare case: Two modifiers at the same time and only 10 max players
have been chosen from `[GameMapType.FaroeIslands]: [20, 15, 10]`.
Because of the 75% reduction in player count only 3 players are allowed
(3 is the minimum). I think its funny that you can play a 1v1v1 in rare
occasions 😄

<img width="526" height="184" alt="Screenshot 2026-01-06 194938"
src="https://github.com/user-attachments/assets/834326eb-df03-41b7-b1db-1efa3f1013b5"
/>

### Funny side-effect

Team games with random spawn. That will be interesting. No more "Who is
better in donating troops to the frontline". Instead you have to heavily
coordinate with your teammates.

## 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:

FloPinguin

src/client/HostLobbyModal.ts

@@ -14,6 +14,7 @@ import {
   UnitType,
   mapCategories,
 } from "../core/game/Game";
+import { getCompactMapNationCount } from "../core/game/NationCreation";
 import { UserSettings } from "../core/game/UserSettings";
 import {
   ClientInfo,
@@ -944,6 +945,7 @@ export class HostLobbyModal extends LitElement {
   /**
    * Returns the effective nation count for display purposes.
    * In HumansVsNations mode, this equals the number of human players.
+   * For compact maps, only 25% of nations are used.
    * Otherwise, it uses the manifest nation count (or 0 if nations are disabled).
    */
   private getEffectiveNationCount(): number {
@@ -953,7 +955,7 @@ export class HostLobbyModal extends LitElement {
     if (this.gameMode === GameMode.Team && this.teamCount === HumansVsNations) {
       return this.clients.length;
     }
-    return this.nationCount;
+    return getCompactMapNationCount(this.nationCount, this.compactMap);
   }
 }
 

src/client/PublicLobby.ts

@@ -7,6 +7,7 @@ import {
   GameMode,
   hasUnusualThumbnailSize,
   HumansVsNations,
+  PublicGameModifiers,
   Quads,
   Trios,
 } from "../core/game/Game";
@@ -114,6 +115,10 @@ export class PublicLobby extends LitElement {
         : `${modeLabel} ${teamDetailLabel}`;
     }
 
+    const modifierLabel = this.getModifierLabels(
+      lobby.gameConfig.publicGameModifiers,
+    );
+
     const mapImageSrc = this.mapImages.get(lobby.gameID);
     const isUnusualThumbnailSize = hasUnusualThumbnailSize(
       lobby.gameConfig.gameMap,
@@ -156,17 +161,29 @@ export class PublicLobby extends LitElement {
                       .join("")}`
                 : translateText("public_lobby.join")}
             </div>
-            <div class="text-md font-medium text-white-400">
-              <span class="text-sm text-blue-600 bg-white rounded-xs px-1 mr-1">
-                ${fullModeLabel}
-              </span>
-              <span>
-                ${translateText(
-                  `map.${lobby.gameConfig.gameMap
-                    .toLowerCase()
-                    .replace(/[\s.]+/g, "")}`,
-                )}
-              </span>
+            <div
+              class="text-md font-medium text-white-400 flex flex-wrap justify-end items-center gap-1"
+            >
+              <span
+                class="text-sm whitespace-nowrap ${this.isLobbyHighlighted
+                  ? "text-green-600"
+                  : "text-blue-600"} bg-white rounded-xs px-1"
+                >${fullModeLabel}</span
+              >
+              ${modifierLabel.map(
+                (label) =>
+                  html`<span
+                    class="text-sm whitespace-nowrap ${this.isLobbyHighlighted
+                      ? "text-green-600"
+                      : "text-blue-600"} bg-white rounded-xs px-1"
+                    >${label}</span
+                  >`,
+              )}
+              <span class="whitespace-nowrap"
+                >${translateText(
+                  `map.${lobby.gameConfig.gameMap.toLowerCase().replace(/[\s.]+/g, "")}`,
+                )}</span
+              >
             </div>
           </div>
 
@@ -293,6 +310,22 @@ export class PublicLobby extends LitElement {
     return { label: null, isFullLabel: false };
   }
 
+  private getModifierLabels(
+    publicGameModifiers: PublicGameModifiers | undefined,
+  ): string[] {
+    if (!publicGameModifiers) {
+      return [];
+    }
+    const labels: string[] = [];
+    if (publicGameModifiers.isRandomSpawn) {
+      labels.push(translateText("public_game_modifier.random_spawn"));
+    }
+    if (publicGameModifiers.isCompact) {
+      labels.push(translateText("public_game_modifier.compact_map"));
+    }
+    return labels;
+  }
+
   private lobbyClicked(lobby: GameInfo) {
     if (this.isButtonDebounced) return;