For v30: Add new modifiers (Hard nations and 25M Starting Gold) 🙂 (#3316)

## Description:

Adds two new public game modifiers for variety and improves compact map
eligibility for team games.

### New Modifiers

**Hard Nations (`isHardNations`)**
- We need this modifier for HvN, because medium nations are easier now
(will result in a much higher human winrate)
- In a discord discussion we concluded that HvN should generally be
easier (higher winrate than 50%, so players are less frustated)
- Thats why only 20% of HvN games have the hard nations modifier (for
now)
- For PvPvE enjoyers, the modifier is also active in FFA games => (Only
2.5% chance, and 1 ticket in `SPECIAL_MODIFIER_POOL`)

**25M Starting Gold (`startingGoldHigh`)**
- Some people in the main discord wanted this modifier, and it will
result in crazy games
- Rare special-only modifier (1 ticket in pool); mutually exclusive with
5M starting gold via `MUTUALLY_EXCLUSIVE_MODIFIERS`
- Disables nations (they lack PVP immunity, so 25M gold doesn't work
well with them)
- Excluded from HumansVsNations games (since it disables nations)
- Spawn immunity set to **2 minutes 30 seconds** (vs 30s for 5M gold),
so people can spend the gold and prepare

### Other Changes

- **Improved `supportsCompactMapForTeams`**: Replaced the hard `smallest
>= 50` land-tile cutoff with a per-team-config calculation that
simulates worst-case compact player count and checks every team gets at
least 2 players.
- **HvN spawn immunity**: Always 5 seconds in both regular and special
lobbies (to get rid of a confusing PVP immunity HeadsUpMessage in 5M
starting gold games)
- **Regular public lobby random spawn modifier probabilty**: Reduced
from 10% to 5% (Because of the new modifier, so there aren't too many
modifiers in non-special-lobbies, should only occur sometimes there)
- Rebalanced `SPECIAL_MODIFIER_POOL` a bit

## 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/GameModeSelector.ts

@@ -5,7 +5,6 @@ import {
   GameMapType,
   GameMode,
   HumansVsNations,
-  PublicGameModifiers,
   Quads,
   Trios,
 } from "../core/game/Game";
@@ -16,7 +15,12 @@ import { PublicLobbySocket } from "./LobbySocket";
 import { JoinLobbyEvent } from "./Main";
 import { SinglePlayerModal } from "./SinglePlayerModal";
 import { terrainMapFileLoader } from "./TerrainMapFileLoader";
-import { getMapName, renderDuration, translateText } from "./Utils";
+import {
+  getMapName,
+  getModifierLabels,
+  renderDuration,
+  translateText,
+} from "./Utils";
 
 const CARD_BG = "bg-[color-mix(in_oklab,var(--frenchBlue)_70%,black)]";
 
@@ -198,7 +202,7 @@ export class GameModeSelector extends LitElement {
 
     const mapName = getMapName(lobby.gameConfig?.gameMap);
 
-    const modifierLabels = this.getModifierLabels(
+    const modifierLabels = getModifierLabels(
       lobby.gameConfig?.publicGameModifiers,
     );
     // Sort by length for visual consistency (shorter labels first)
@@ -283,16 +287,6 @@ export class GameModeSelector extends LitElement {
     );
   }
 
-  private getModifierLabels(mods: PublicGameModifiers | undefined): string[] {
-    if (!mods) return [];
-    return [
-      mods.isRandomSpawn && translateText("public_game_modifier.random_spawn"),
-      mods.isCompact && translateText("public_game_modifier.compact_map"),
-      mods.isCrowded && translateText("public_game_modifier.crowded"),
-      mods.startingGold && translateText("public_game_modifier.starting_gold"),
-    ].filter((x): x is string => !!x);
-  }
-
   private getLobbyTitle(lobby: PublicGameInfo): string {
     const config = lobby.gameConfig!;
     if (config.gameMode === GameMode.FFA) {

src/client/Utils.ts

@@ -109,6 +109,8 @@ export interface ModifierInfo {
   labelKey: string;
   /** Translation key for badge/short label (e.g. "public_game_modifier.random_spawn") */
   badgeKey: string;
+  /** Parameters to pass to translateText for the badge key */
+  badgeParams?: Record<string, string | number>;
   /** The raw value if applicable (e.g. startingGold amount) */
   value?: number;
 }
@@ -139,10 +141,19 @@ export function getActiveModifiers(
       badgeKey: "public_game_modifier.crowded",
     });
   }
+  if (modifiers.isHardNations) {
+    result.push({
+      labelKey: "host_modal.hard_nations",
+      badgeKey: "public_game_modifier.hard_nations",
+    });
+  }
   if (modifiers.startingGold) {
     result.push({
       labelKey: "host_modal.starting_gold",
       badgeKey: "public_game_modifier.starting_gold",
+      badgeParams: {
+        amount: Math.round(modifiers.startingGold / 1_000_000),
+      },
       value: modifiers.startingGold,
     });
   }
@@ -155,7 +166,9 @@ export function getActiveModifiers(
 export function getModifierLabels(
   modifiers: PublicGameModifiers | undefined,
 ): string[] {
-  return getActiveModifiers(modifiers).map((m) => translateText(m.badgeKey));
+  return getActiveModifiers(modifiers).map((m) =>
+    translateText(m.badgeKey, m.badgeParams),
+  );
 }
 
 export function renderDuration(totalSeconds: number): string {