feat(portals): add craftable portal blocks replacing hardcoded coordinates

Portal frame crafted from obsidian + ender pearl, combined with crystals
(emerald/amethyst/prismarine) to create world-specific portal blocks.
Stepping on a portal block triggers transfer. Includes resource pack with
vanilla textures, block definitions, crafting recipes, and updated script.

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

docker-compose.yml

@@ -19,6 +19,7 @@ services:
     volumes:
       - lobby-data:/data
       - ./lobby-addon/lobby_transfer_BP:/data/behavior_packs/lobby_transfer_BP
+      - ./lobby-addon/lobby_transfer_RP:/data/resource_packs/lobby_transfer_RP
       - ./addon/spark_pet_BP:/data/behavior_packs/spark_pet_BP
       - ./addon/spark_pet_RP:/data/resource_packs/spark_pet_RP
     restart: unless-stopped