feat: add multi-world hub system with lobby portals and hub-return addon

Lobby addon detects players in portal zones at X: -15/0/15 and transfers
them to Jamie/Lyla/Mya survival worlds. Hub-return addon gives players a
recovery compass and chat commands (!hub, !lobby) to return to the lobby.

Includes docker-compose.yml for 4 Bedrock servers (lobby + 3 child worlds),
spark pet behavior/resource packs, and updated .gitignore.

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

lobby-addon/lobby_transfer_BP/scripts/main.js

@@ -0,0 +1,53 @@
+import { world, system } from "@minecraft/server";
+
+// Portal definitions: name, center position, and direct transfer target
+const portals = [
+  { name: "Jamie's World", x: -15, y: 65, z: -24, host: "10.0.0.247", port: 19133 },
+  { name: "Lyla's World",  x: 0,   y: 65, z: -24, host: "10.0.0.247", port: 19134 },
+  { name: "Mya's World",   x: 15,  y: 65, z: -24, host: "10.0.0.247", port: 19135 },
+];
+
+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
+
+// Track cooldowns per player
+const cooldowns = new Map();
+
+system.runInterval(() => {
+  for (const player of world.getAllPlayers()) {
+    const pos = player.location;
+    const playerId = player.id;
+
+    // Check cooldown
+    const lastTransfer = cooldowns.get(playerId) || 0;
+    if (system.currentTick - lastTransfer < COOLDOWN_TICKS) continue;
+
+    for (const portal of portals) {
+      const dx = Math.abs(pos.x - portal.x);
+      const dy = Math.abs(pos.y - portal.y);
+      const dz = Math.abs(pos.z - portal.z);
+
+      if (dx < PORTAL_RADIUS_X && dy < PORTAL_RADIUS_Y && dz < PORTAL_RADIUS_Z) {
+        cooldowns.set(playerId, system.currentTick);
+        player.sendMessage(`§6Transferring to ${portal.name}...`);
+        try {
+          player.runCommand(`transfer "${player.name}" ${portal.host} ${portal.port}`);
+        } catch (e) {
+          player.sendMessage(`§cTransfer failed: ${e.message}`);
+        }
+        break;
+      }
+    }
+  }
+}, 10); // Check every half second
+
+// Clean up cooldowns when players leave
+world.afterEvents.playerLeave.subscribe((event) => {
+  cooldowns.delete(event.playerId);
+});
+
+system.run(() => {
+  world.sendMessage("§6[Hub] §7Portal transfer system loaded!");
+});