feat(datapacks): add ironchest recipes and datapack sync automation

- Add crafting recipes for copper, iron, gold, and diamond chests using IronChest mod
- Remove vanilla copper chest recipe to prevent conflicts
- Introduce `.env.example` for local world configuration
- Add `bash/sync-datapacks-to-world.sh` script to mirror datapacks to Minecraft world saves
  - Supports one-time sync and watch mode for real-time updates
  - Uses `rsync` for efficient file synchronization

datapacks/m2621/data/ironchest/recipe/iron_chest.json

@@ -0,0 +1,15 @@
+{
+  "type": "minecraft:crafting_shaped",
+  "pattern": [
+    "III",
+    "ISI",
+    "III"
+  ],
+  "key": {
+    "I": "minecraft:iron_ingot",
+    "S": "ironchest:copper_chest"
+  },
+  "result": {
+    "id": "ironchest:iron_chest"
+  }
+}