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>

docker-compose.yml

@@ -0,0 +1,114 @@
+services:
+  lobby:
+    image: itzg/minecraft-bedrock-server
+    container_name: mc-lobby
+    environment:
+      EULA: "TRUE"
+      SERVER_NAME: "SilverLABS Hub"
+      GAMEMODE: adventure
+      DIFFICULTY: peaceful
+      ALLOW_CHEATS: "true"
+      ONLINE_MODE: "false"
+      SERVER_PORT: "19132"
+      LEVEL_NAME: "Hub World"
+      MAX_PLAYERS: "10"
+      DEFAULT_PLAYER_PERMISSION_LEVEL: operator
+      OP_PERMISSION_LEVEL: "4"
+    ports:
+      - "${LOBBY_PORT:-19132}:19132/udp"
+    volumes:
+      - lobby-data:/data
+      - ./lobby-addon/lobby_transfer_BP:/data/behavior_packs/lobby_transfer_BP
+      - ./addon/spark_pet_BP:/data/behavior_packs/spark_pet_BP
+      - ./addon/spark_pet_RP:/data/resource_packs/spark_pet_RP
+    restart: unless-stopped
+    networks:
+      - mc-network
+
+  jamie:
+    image: itzg/minecraft-bedrock-server
+    container_name: mc-jamie
+    environment:
+      EULA: "TRUE"
+      SERVER_NAME: "Jamie's World"
+      GAMEMODE: survival
+      DIFFICULTY: normal
+      ALLOW_CHEATS: "true"
+      ONLINE_MODE: "false"
+      SERVER_PORT: "19132"
+      LEVEL_NAME: "Jamie World"
+      MAX_PLAYERS: "10"
+      DEFAULT_PLAYER_PERMISSION_LEVEL: operator
+      OP_PERMISSION_LEVEL: "4"
+    ports:
+      - "${JAMIE_PORT:-19133}:19132/udp"
+    volumes:
+      - jamie-data:/data
+      - ./hub-return-addon/hub_return_transfer_BP:/data/behavior_packs/hub_return_transfer_BP
+      - ./addon/spark_pet_BP:/data/behavior_packs/spark_pet_BP
+      - ./addon/spark_pet_RP:/data/resource_packs/spark_pet_RP
+    restart: unless-stopped
+    networks:
+      - mc-network
+
+  lyla:
+    image: itzg/minecraft-bedrock-server
+    container_name: mc-lyla
+    environment:
+      EULA: "TRUE"
+      SERVER_NAME: "Lyla's World"
+      GAMEMODE: survival
+      DIFFICULTY: normal
+      ALLOW_CHEATS: "true"
+      ONLINE_MODE: "false"
+      SERVER_PORT: "19132"
+      LEVEL_NAME: "Lyla World"
+      MAX_PLAYERS: "10"
+      DEFAULT_PLAYER_PERMISSION_LEVEL: operator
+      OP_PERMISSION_LEVEL: "4"
+    ports:
+      - "${LYLA_PORT:-19134}:19132/udp"
+    volumes:
+      - lyla-data:/data
+      - ./hub-return-addon/hub_return_transfer_BP:/data/behavior_packs/hub_return_transfer_BP
+      - ./addon/spark_pet_BP:/data/behavior_packs/spark_pet_BP
+      - ./addon/spark_pet_RP:/data/resource_packs/spark_pet_RP
+    restart: unless-stopped
+    networks:
+      - mc-network
+
+  mya:
+    image: itzg/minecraft-bedrock-server
+    container_name: mc-mya
+    environment:
+      EULA: "TRUE"
+      SERVER_NAME: "Mya's World"
+      GAMEMODE: survival
+      DIFFICULTY: normal
+      ALLOW_CHEATS: "true"
+      ONLINE_MODE: "false"
+      SERVER_PORT: "19132"
+      LEVEL_NAME: "Mya World"
+      MAX_PLAYERS: "10"
+      DEFAULT_PLAYER_PERMISSION_LEVEL: operator
+      OP_PERMISSION_LEVEL: "4"
+    ports:
+      - "${MYA_PORT:-19135}:19132/udp"
+    volumes:
+      - mya-data:/data
+      - ./hub-return-addon/hub_return_transfer_BP:/data/behavior_packs/hub_return_transfer_BP
+      - ./addon/spark_pet_BP:/data/behavior_packs/spark_pet_BP
+      - ./addon/spark_pet_RP:/data/resource_packs/spark_pet_RP
+    restart: unless-stopped
+    networks:
+      - mc-network
+
+volumes:
+  lobby-data:
+  jamie-data:
+  lyla-data:
+  mya-data:
+
+networks:
+  mc-network:
+    driver: bridge