feat: Introduce GameConfig to centralize constants for leveling, economy, and inventory, adding new transfer and inventory limits.

src/config/game.ts

@@ -0,0 +1,29 @@
+export const GameConfig = {
+    leveling: {
+        // Curve: Base * (Level ^ Exponent)
+        base: 100,
+        exponent: 2.5,
+
+        chat: {
+            cooldownMs: 60000, // 1 minute
+            minXp: 15,
+            maxXp: 25,
+        }
+    },
+    economy: {
+        daily: {
+            amount: 100n,
+            streakBonus: 10n,
+            cooldownMs: 24 * 60 * 60 * 1000, // 24 hours
+        },
+        transfers: {
+            // Future use
+            allowSelfTransfer: false,
+            minAmount: 1n,
+        }
+    },
+    inventory: {
+        maxStackSize: 999n,
+        maxSlots: 50,
+    }
+} as const;