fix(transfer): use transferPlayer() beta API and enable experiments in level.dat

Switch from runCommand("transfer ...") to the @minecraft/server-admin
transferPlayer() function for reliable server-to-server transfers.
Enable Beta APIs experiment (gametest flag) in all 4 world level.dat files.
Add spawn protection to prevent transfer loops on arrival.

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

lobby-addon/lobby_transfer_BP/manifest.json

@@ -4,7 +4,7 @@
     "name": "Lobby Portal Transfer",
     "description": "Auto-transfers players when they step into portal areas",
     "uuid": "a1b2c3d4-1111-2222-3333-abcdef123456",
-    "version": [1, 0, 1],
+    "version": [1, 0, 3],
     "min_engine_version": [1, 21, 0]
   },
   "modules": [
@@ -12,14 +12,18 @@
       "type": "script",
       "language": "javascript",
       "uuid": "a1b2c3d4-4444-5555-6666-abcdef789012",
-      "version": [1, 0, 1],
+      "version": [1, 0, 3],
       "entry": "scripts/main.js"
     }
   ],
   "dependencies": [
     {
       "module_name": "@minecraft/server",
-      "version": "2.0.0"
+      "version": "1.17.0"
+    },
+    {
+      "module_name": "@minecraft/server-admin",
+      "version": "1.0.0-beta"
     }
   ]
 }

lobby-addon/lobby_transfer_BP/scripts/main.js

@@ -1,4 +1,5 @@
 import { world, system } from "@minecraft/server";
+import { transferPlayer } from "@minecraft/server-admin";
 
 // Portal definitions: name, center position, and direct transfer target
 const portals = [
@@ -11,9 +12,16 @@ const PORTAL_RADIUS_X = 2.5;
 const PORTAL_RADIUS_Z = 2.0;
 const PORTAL_RADIUS_Y = 2.0;
 const COOLDOWN_TICKS = 100; // 5 seconds cooldown
+const SPAWN_PROTECTION_TICKS = 200; // 10 seconds — ignore portal detection after spawn
 
 // Track cooldowns per player
 const cooldowns = new Map();
+// Track when players spawned (to prevent transfer loop on arrival)
+const spawnTicks = new Map();
+
+world.afterEvents.playerSpawn.subscribe((event) => {
+  spawnTicks.set(event.player.id, system.currentTick);
+});
 
 system.runInterval(() => {
   for (const player of world.getAllPlayers()) {
@@ -24,6 +32,10 @@ system.runInterval(() => {
     const lastTransfer = cooldowns.get(playerId) || 0;
     if (system.currentTick - lastTransfer < COOLDOWN_TICKS) continue;
 
+    // Skip if player just spawned (prevents loop when arriving from child world)
+    const spawnedAt = spawnTicks.get(playerId) || 0;
+    if (system.currentTick - spawnedAt < SPAWN_PROTECTION_TICKS) continue;
+
     for (const portal of portals) {
       const dx = Math.abs(pos.x - portal.x);
       const dy = Math.abs(pos.y - portal.y);
@@ -33,7 +45,7 @@ system.runInterval(() => {
         cooldowns.set(playerId, system.currentTick);
         player.sendMessage(`§6Transferring to ${portal.name}...`);
         try {
-          player.runCommand(`transfer ${player.name} ${portal.host} ${portal.port}`);
+          transferPlayer(player, { hostname: portal.host, port: portal.port });
         } catch (e) {
           player.sendMessage(`§cTransfer failed: ${e.message}`);
         }
@@ -43,9 +55,10 @@ system.runInterval(() => {
   }
 }, 10); // Check every half second
 
-// Clean up cooldowns when players leave
+// Clean up tracking when players leave
 world.afterEvents.playerLeave.subscribe((event) => {
   cooldowns.delete(event.playerId);
+  spawnTicks.delete(event.playerId);
 });
 
 system.run(() => {