feat(games): implement chess game plugin with full UI

Add chess as the first game plugin using the existing multiplayer framework.
Server-side game logic uses chess.js with server-authoritative clock management.
Client uses react-chessboard v5 with cburnett piece set, drag-and-drop + click-to-move,
configurable time controls (bullet/blitz/rapid/classical/none), draw offers,
resignation, and timeout detection. Extends the game framework with room creation
options to support per-game configuration. Includes 57 tests covering all code paths.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/src/games/GameServer.ts

@@ -117,7 +117,7 @@ export class GameServer {
 
         switch (msg.type) {
             case "CREATE_ROOM": {
-                const result = this.roomManager.createRoom(msg.gameType, discordId);
+                const result = this.roomManager.createRoom(msg.gameType, discordId, msg.options);
                 if (!result.ok) {
                     ws.send(JSON.stringify({ type: "ERROR", message: result.error }));
                     return;

api/src/games/RoomManager.ts

@@ -33,7 +33,7 @@ export class RoomManager {
     private cleanupTimers = new Map<string, Timer>();
     readonly emitter = mitt<RoomEvents>();
 
-    createRoom(gameSlug: string, hostId: string): CreateResult {
+    createRoom(gameSlug: string, hostId: string, options?: Record<string, unknown>): CreateResult {
         const plugin = gameRegistry.get(gameSlug);
         if (!plugin) return { ok: false, error: `Unknown game type: ${gameSlug}` };
 
@@ -47,6 +47,7 @@ export class RoomManager {
             state: null,
             status: "waiting",
             createdAt: Date.now(),
+            options,
         };
 
         this.rooms.set(id, room);
@@ -85,7 +86,7 @@ export class RoomManager {
         room.players.push(playerId);
 
         if (room.players.length >= plugin.maxPlayers) {
-            room.state = plugin.createInitialState(room.players);
+            room.state = plugin.createInitialState(room.players, room.options);
             room.status = "playing";
             this.scheduleCleanup(roomId, ROOM_CONFIG.PLAYING_MAX_MS);
 
@@ -185,7 +186,7 @@ export class RoomManager {
             room.players.push(adminId);
         }
 
-        room.state = plugin.createInitialState(room.players);
+        room.state = plugin.createInitialState(room.players, room.options);
         room.status = "playing";
         this.scheduleCleanup(roomId, ROOM_CONFIG.PLAYING_MAX_MS);
 

api/src/games/types.ts

@@ -9,6 +9,7 @@ export interface Room {
     state: unknown;
     status: "waiting" | "playing" | "finished";
     createdAt: number;
+    options?: Record<string, unknown>;
 }
 
 export interface RoomSummary {
@@ -28,7 +29,7 @@ export interface PlayerInfo {
 }
 
 export const GameWsClientSchema = z.discriminatedUnion("type", [
-    z.object({ type: z.literal("CREATE_ROOM"), gameType: z.string() }),
+    z.object({ type: z.literal("CREATE_ROOM"), gameType: z.string(), options: z.looseObject({}).optional() }),
     z.object({
         type: z.literal("JOIN_ROOM"),
         roomId: z.string(),

api/src/server.ts

@@ -18,6 +18,11 @@ import type { WsConnectionData } from "./games/GameServer";
 import { getSession } from "./routes/auth.routes";
 import { GameWsClientSchema } from "./games/types";
 
+// Register game plugins
+import { gameRegistry } from "@shared/games/registry";
+import { chessPlugin } from "@shared/games/chess/chess.plugin";
+gameRegistry.register(chessPlugin);
+
 const WS_CONFIG = {
     MAX_CONNECTIONS: 200,
     MAX_PAYLOAD_BYTES: 16384,