Halloween Event (#2285)

## Description:

Changed theme colors for an "autumn" ambiance:

<img width="395" height="254" alt="image"
src="https://github.com/user-attachments/assets/67bd07d3-e74b-49e2-ba0b-c87958767d45"
/>

Changed structures pixel art:

<img width="756" height="605" alt="image"
src="https://github.com/user-attachments/assets/5158ae81-0641-413c-8862-367259496a9a"
/>


Change existing FX with new halloween-themed ones:


https://github.com/user-attachments/assets/fb99be49-43cd-4d85-ad77-8c153070edaf

Added new FX playing randomly on the map:


https://github.com/user-attachments/assets/16631113-77e6-4b8c-b1b6-c147f5f1d275

Added a couple of new emojis, which are used by the bots when attacked:
👻🎃

## 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:

IngloriousTom

src/client/graphics/SpriteLoader.ts

@@ -1,6 +1,6 @@
 import { Colord } from "colord";
-import atomBombSprite from "../../../resources/sprites/atombomb.png";
-import hydrogenBombSprite from "../../../resources/sprites/hydrogenbomb.png";
+import miniPumpkin from "../../../resources/sprites/halloween/miniPumpkin.png";
+import pumpkin from "../../../resources/sprites/halloween/pumpkin.png";
 import mirvSprite from "../../../resources/sprites/mirv2.png";
 import samMissileSprite from "../../../resources/sprites/samMissile.png";
 import tradeShipSprite from "../../../resources/sprites/tradeship.png";
@@ -26,8 +26,8 @@ const SPRITE_CONFIG: Partial<Record<UnitType | TrainTypeSprite, string>> = {
   [UnitType.TransportShip]: transportShipSprite,
   [UnitType.Warship]: warshipSprite,
   [UnitType.SAMMissile]: samMissileSprite,
-  [UnitType.AtomBomb]: atomBombSprite,
-  [UnitType.HydrogenBomb]: hydrogenBombSprite,
+  [UnitType.AtomBomb]: miniPumpkin,
+  [UnitType.HydrogenBomb]: pumpkin,
   [UnitType.TradeShip]: tradeShipSprite,
   [UnitType.MIRV]: mirvSprite,
   [TrainTypeSprite.Engine]: trainEngineSprite,