MLS for Quick Chat (#686)

## Description:
<img width="842" alt="スクリーンショット 2025-05-09 17 51 27"
src="https://github.com/user-attachments/assets/b9a2cb5b-74d2-4c07-aed2-01d719de6eb4"
/>

MLS
## 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

src/core/game/Game.ts

@@ -509,6 +509,15 @@ export interface Game extends GameMap {
     playerID: PlayerID | null,
   ): void;
 
+  displayChat(
+    message: string,
+    category: string,
+    variables: Record<string, string>,
+    playerID: PlayerID | null,
+    isFrom: boolean,
+    recipient: string,
+  ): void;
+
   // Nations
   nations(): Nation[];
 

src/core/game/GameImpl.ts

@@ -606,6 +606,28 @@ export class GameImpl implements Game {
     });
   }
 
+  displayChat(
+    message: string,
+    category: string,
+    variables: Record<string, string> = {},
+    playerID: PlayerID | null,
+    isFrom: boolean | null = null,
+    recipient: string,
+  ): void {
+    let id = null;
+    if (playerID != null) {
+      id = this.player(playerID).smallID();
+    }
+    this.addUpdate({
+      type: GameUpdateType.DisplayChatEvent,
+      key: message,
+      category: category,
+      variables: variables,
+      playerID: id,
+      isFrom: isFrom,
+      recipient: recipient,
+    });
+  }
   addUnit(u: Unit) {
     this.unitGrid.addUnit(u);
   }

src/core/game/GameUpdates.ts

@@ -29,6 +29,7 @@ export enum GameUpdateType {
   Unit,
   Player,
   DisplayEvent,
+  DisplayChatEvent,
   AllianceRequest,
   AllianceRequestReply,
   BrokeAlliance,
@@ -48,6 +49,7 @@ export type GameUpdate =
   | BrokeAllianceUpdate
   | AllianceExpiredUpdate
   | DisplayMessageUpdate
+  | DisplayChatMessageUpdate
   | TargetPlayerUpdate
   | EmojiUpdate
   | WinUpdate
@@ -157,6 +159,16 @@ export interface DisplayMessageUpdate {
   playerID: number | null;
 }
 
+export type DisplayChatMessageUpdate = {
+  type: GameUpdateType.DisplayChatEvent;
+  key: string;
+  category: string;
+  variables?: Record<string, string>;
+  playerID: number | null;
+  isFrom: boolean;
+  recipient: string;
+};
+
 export interface WinUpdate {
   type: GameUpdateType.Win;
   allPlayersStats: AllPlayersStats;