Fix attack crash: provide empty item when hand is empty

The inventory_transaction packet for attacks includes held_item.
When Doug has nothing in his hand, bot.heldItem is null, causing
"Cannot read properties of null (reading 'network_id')".

Fix: provide a proper empty item object with network_id=0 when
heldItem is null. Attacks now send successfully.

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

bridge/lib/mineflayer/lib/bedrockPlugins/entities.mts

@@ -523,6 +523,16 @@ export default function inject(bot: BedrockBot) {
   }
   function itemUseOnEntity(target: any, type: number) {
     const typeStr = ['attack', 'interact'][type];
+    // Provide empty item if hand is empty to avoid serialization crash
+    const heldItem = bot.heldItem || {
+      network_id: 0,
+      count: 0,
+      metadata: 0,
+      has_stack_id: false,
+      stack_id: 0,
+      block_runtime_id: 0,
+      extra: { has_nbt: false, can_place_on: [], can_destroy: [] },
+    };
     const transaction = {
       transaction: {
         legacy: {
@@ -534,10 +544,9 @@ export default function inject(bot: BedrockBot) {
           entity_runtime_id: target.id,
           action_type: typeStr,
           hotbar_slot: bot.quickBarSlot,
-          held_item: bot.heldItem,
+          held_item: heldItem,
           player_pos: bot.entity.position,
           click_pos: {
-            // in case with interact its pos on hitbox of entity that is being interacted with
             x: 0,
             y: 0,
             z: 0,