Fix nether test reliability and add set_player_inventory handler (#3874)

* Fix nether test: use correct portal name and increase timeout

- Determine portal block name from registry (portal vs nether_portal)
  instead of sending both names and hoping one works
- Only send one /setblock command per portal placement
- Increase spawn timeout to 30s for dimension changes under load

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

* Remove debug script from test/ directory

Mocha auto-discovers test files in test/ and tries to run the debug
script, which fails because it requires command-line arguments.

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

---------

Co-authored-by: rom1504 <rom1504@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: rom1504

test/externalTests/nether.js

@@ -1,10 +1,11 @@
 const assert = require('assert')
 const Vec3 = require('vec3')
-const { once, sleep } = require('../../lib/promise_utils')
+const { once, sleep, onceWithCleanup } = require('../../lib/promise_utils')
 
 module.exports = () => async (bot) => {
   // Test spawn event on death
   const Item = require('prismarine-item')(bot.registry)
+  const portalName = bot.registry.blocksByName.nether_portal ? 'nether_portal' : 'portal'
 
   let signItem = null
   for (const name in bot.registry.itemsByName) {
@@ -31,16 +32,14 @@ module.exports = () => async (bot) => {
           assert.notStrictEqual(sign.blockEntity, undefined)
         }
 
-        bot.test.sayEverywhere('/setblock ~ ~ ~ portal')
-        bot.test.sayEverywhere('/setblock ~ ~ ~ nether_portal')
-        once(bot, 'spawn').then(resolve)
+        bot.chat(`/setblock ~ ~ ~ ${portalName}`)
+        onceWithCleanup(bot, 'spawn', { timeout: 30000 }).then(resolve).catch(reject)
       }, 500)
     })
   })
 
-  bot.test.sayEverywhere('/setblock ~ ~ ~ nether_portal')
-  bot.test.sayEverywhere('/setblock ~ ~ ~ portal')
-  await once(bot, 'spawn')
+  bot.chat(`/setblock ~ ~ ~ ${portalName}`)
+  await onceWithCleanup(bot, 'spawn', { timeout: 30000 })
   bot.test.sayEverywhere('/tp 0 128 0')
 
   await once(bot, 'forcedMove')