feat: refactor Nakama plugin into generic multi-game match engine

### Highlights
- Introduced generic match engine (`generic_match.go`) implementing dynamic GameRules-based runtime.
- Added modular structure under `/plugins`:
  - /plugins/game      → GameRules interface + TicTacToe + Battleship rule sets
  - /plugins/structs   → Board, Player, MatchState generic structs
  - /plugins/modules   → matchmaking + RPC handlers + match engine
- Migrated TicTacToe logic into reusable rule implementation.
- Added Battleship game support using same engine.
- Updated matchmaking to accept { game, mode } for multi-game routing.
- Updated UI contract: clients must send `game` (and optional `mode`) when joining matchmaking.
- Removed hardcoded TicTacToe match registration.
- Registered a single “generic” authoritative match with ruleset registry.
- Normalized imports under local dev module path.
- Ensured MatchState and Board are now generic and reusable across games.
- Added strict requirement for `game` metadata in match flow (error if missing).
- Cleaned initial state creation into MatchInit with flexible board dimensions.
- Improved MatchLeave for proper forfeit handling through GameRules.

### Result
The server now supports an unlimited number of turn-based board games
via swappable rulesets while keeping a single authoritative Nakama match loop.

plugins/main.go

@@ -5,61 +5,87 @@ import (
 	"database/sql"
 
 	"github.com/heroiclabs/nakama-common/runtime"
+
+	// Adjust these imports to match your project structure
+	"localrepo/plugins/modules"
+	"localrepo/plugins/games"
 )
 
-// Example RPC
-func HelloWorld(
+func InitModule(
 	ctx context.Context,
 	logger runtime.Logger,
 	db *sql.DB,
 	nk runtime.NakamaModule,
-	payload string,
-) (string, error) {
-	logger.Info("HelloWorld RPC called — payload: %s", payload)
-	return `{"message": "Hello from Go RPC!"}`, nil
-}
-
-// Required module initializer
-func InitModule(
-  ctx context.Context,
-  logger runtime.Logger,
-  db *sql.DB,
-  nk runtime.NakamaModule,
-  initializer runtime.Initializer,
+	initializer runtime.Initializer,
 ) error {
+
+	//--------------------------------------------------------
+	// 1. Register RPCs
+	//--------------------------------------------------------
 	if err := initializer.RegisterRpc("hello_world", HelloWorld); err != nil {
-		logger.Error("Failed to register RPC: %v", err)
-		return err
-	}
-	if err := initializer.RegisterMatch("tictactoe", NewMatch); err != nil {
-		logger.Error("Failed to register RPC: %v", err)
-		return err
-	}
-  // Match making
-	if err := initializer.RegisterRpc("leave_matchmaking", rpcLeaveMatchmaking); err != nil {
-		logger.Error("RegisterRpc leave_matchmaking failed: %v", err)
-		return err
-	}
-	if err := initializer.RegisterMatchmakerMatched(MatchmakerMatched); err != nil {
-		logger.Error("RegisterMatchmakerMatched failed: %v", err)
+		logger.Error("Failed to register RPC hello_world: %v", err)
 		return err
 	}
 
-  err := nk.LeaderboardCreate(
-    ctx,
-    "tictactoe",  // id
-    true,                     // authoritative
-    "desc",                   // sortOrder
-    "incr",                   // operator
-    "",                       // resetSchedule
-    map[string]interface{}{}, // metadata
-  )
+	if err := initializer.RegisterRpc("leave_matchmaking", modules.RpcLeaveMatchmaking); err != nil {
+		logger.Error("Failed to register RPC leave_matchmaking: %v", err)
+		return err
+	}
 
-  if err != nil && err.Error() != "Leaderboard ID already exists" {
-    return err
-  }
+	//--------------------------------------------------------
+	// 2. Register Matchmaker Handler
+	//--------------------------------------------------------
+	if err := initializer.RegisterMatchmakerMatched(modules.MatchmakerMatched); err != nil {
+		logger.Error("Failed to register MatchmakerMatched: %v", err)
+		return err
+	}
+
+	//--------------------------------------------------------
+	// 3. Register MATCHES for ALL games
+	//--------------------------------------------------------
+
+	// Build registry: game name → GameRules implementation
+	registry := map[string]game.GameRules{
+		"tictactoe":  &game.TicTacToeRules{},
+		"battleship": &game.BattleshipRules{},
+	}
+
+	// Register a Generic Match Handler that can run ANY game from registry
+	if err := initializer.RegisterMatch("generic", modules.NewGenericMatch(registry)); err != nil {
+		logger.Error("Failed to register generic match: %v", err)
+		return err
+	}
+
+	//--------------------------------------------------------
+	// 4. Register Leaderboards dynamically (optional)
+	//--------------------------------------------------------
+
+	leaderboards := []string{
+		"tictactoe_classic",
+		"tictactoe_ranked",
+		"battleship_classic",
+		"battleship_ranked",
+	}
+
+	for _, lb := range leaderboards {
+		err := nk.LeaderboardCreate(
+			ctx,
+			lb,                      // leaderboard ID
+			true,                    // authoritative
+			"desc",                  // sort order
+			"incr",                  // operator
+			"",                      // reset schedule (none)
+			map[string]interface{}{}, // metadata
+		)
+
+		if err != nil && err.Error() != "Leaderboard ID already exists" {
+			logger.Error("Failed to create leaderboard %s: %v", lb, err)
+			return err
+		}
+
+		logger.Info("Leaderboard ready: %s", lb)
+	}
 
-  logger.Info("Leaderboard tictactoe ready")
 	logger.Info("Go module loaded successfully!")
 	return nil
 }