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_RP/manifest.json

@@ -0,0 +1,23 @@
+{
+  "format_version": 2,
+  "header": {
+    "name": "Pets 4 Jamie's STARS Resources",
+    "description": "Textures, models and animations for Pets 4 Jamie's STARS",
+    "uuid": "5f25d547-00bb-49ce-8be3-d86cd3941c9b",
+    "version": [1, 0, 0],
+    "min_engine_version": [1, 21, 0]
+  },
+  "modules": [
+    {
+      "type": "resources",
+      "uuid": "6adc20cd-25a5-4ca5-aa12-f5e43ee9ea22",
+      "version": [1, 0, 0]
+    }
+  ],
+  "dependencies": [
+    {
+      "uuid": "7cf924ce-e246-4c8c-998c-f420edb26451",
+      "version": [1, 0, 0]
+    }
+  ]
+}