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>

addon/spark_pet_BP/items/dragon_bones.json

@@ -0,0 +1,19 @@
+{
+  "format_version": "1.21.120",
+  "minecraft:item": {
+    "description": {
+      "identifier": "silverlabs:dragon_bones",
+      "menu_category": {
+        "category": "items"
+      }
+    },
+    "components": {
+      "minecraft:icon": "dragon_bones",
+      "minecraft:display_name": {
+        "value": "item.silverlabs:dragon_bones.name"
+      },
+      "minecraft:max_stack_size": 1,
+      "minecraft:glint": true
+    }
+  }
+}

addon/spark_pet_BP/items/dragon_egg.json

@@ -0,0 +1,22 @@
+{
+  "format_version": "1.21.120",
+  "minecraft:item": {
+    "description": {
+      "identifier": "silverlabs:dragon_egg",
+      "menu_category": {
+        "category": "items"
+      }
+    },
+    "components": {
+      "minecraft:icon": "dragon_egg",
+      "minecraft:display_name": {
+        "value": "item.silverlabs:dragon_egg.name"
+      },
+      "minecraft:max_stack_size": 1,
+      "minecraft:glint": true,
+      "minecraft:entity_placer": {
+        "entity": "silverlabs:dragon_egg"
+      }
+    }
+  }
+}

addon/spark_pet_BP/items/dragon_gravestone.json

@@ -0,0 +1,22 @@
+{
+  "format_version": "1.21.120",
+  "minecraft:item": {
+    "description": {
+      "identifier": "silverlabs:dragon_gravestone",
+      "menu_category": {
+        "category": "items"
+      }
+    },
+    "components": {
+      "minecraft:icon": "dragon_gravestone",
+      "minecraft:display_name": {
+        "value": "item.silverlabs:dragon_gravestone.name"
+      },
+      "minecraft:max_stack_size": 1,
+      "minecraft:glint": true,
+      "minecraft:entity_placer": {
+        "entity": "silverlabs:dragon_gravestone"
+      }
+    }
+  }
+}

addon/spark_pet_BP/items/dragon_toy.json

@@ -0,0 +1,26 @@
+{
+  "format_version": "1.21.0",
+  "minecraft:item": {
+    "description": {
+      "identifier": "silverlabs:dragon_toy",
+      "menu_category": {
+        "category": "items"
+      }
+    },
+    "components": {
+      "minecraft:icon": "dragon_toy",
+      "minecraft:display_name": {
+        "value": "item.silverlabs:dragon_toy.name"
+      },
+      "minecraft:max_stack_size": 16,
+      "minecraft:throwable": {
+        "do_swing_animation": true,
+        "max_draw_duration": 0,
+        "scale_power_by_draw_duration": false
+      },
+      "minecraft:projectile": {
+        "projectile_entity": "silverlabs:dragon_toy"
+      }
+    }
+  }
+}

addon/spark_pet_BP/items/dragon_whistle.json

@@ -0,0 +1,26 @@
+{
+  "format_version": "1.21.0",
+  "minecraft:item": {
+    "description": {
+      "identifier": "silverlabs:dragon_whistle",
+      "menu_category": {
+        "category": "items"
+      }
+    },
+    "components": {
+      "minecraft:icon": "dragon_whistle",
+      "minecraft:display_name": {
+        "value": "item.silverlabs:dragon_whistle.name"
+      },
+      "minecraft:max_stack_size": 16,
+      "minecraft:throwable": {
+        "do_swing_animation": true,
+        "max_draw_duration": 0,
+        "scale_power_by_draw_duration": false
+      },
+      "minecraft:projectile": {
+        "projectile_entity": "silverlabs:whistle_signal"
+      }
+    }
+  }
+}