[RobioEpo]

fix: ServerboundPlaceRecipe sends a resource location where 1.21.2+ reads a RecipeDisplayId

What's wrong

ServerboundPlaceRecipe serializes its second field as an Identifier (a resource-location
string). Since 1.21.2 that field is a RecipeDisplayId — a VarInt. A real craft therefore
writes ~23 bytes where the server reads 3, and the server disconnects the client:

DecoderException: Packet serverbound/minecraft:place_recipe (ServerboundPlaceRecipePacket)
was larger than I expected, found 20 bytes extra whilst reading packet
serverbound/minecraft:place_recipe

Reproduced (azalea's own code)

Serializing the real packet with AzBuf (ServerboundPlaceRecipe { container_id: 0, recipe: Identifier::new("minecraft:oak_planks"), shift_down: true }) gives, on current main/ddef371:

azalea writes 23 bytes: [0, 20, "minecraft:oak_planks"(20), 1]

VarInt(containerId=0) · VarInt(len=20) · the 20-byte string · bool = 23 bytes.
The 1.21.2+ server reads VarInt(containerId) + VarInt(RecipeDisplayId) + bool = 3, so it
reports 20 bytes extra — exactly the disconnect above.

Evidence

• NeoForge 26.1: record ServerboundPlaceRecipePacket(int containerId, RecipeDisplayId recipe, boolean useMaxItems).
• mappings.dev 1.21.10: the field is RecipeDisplayId.
• PacketEvents: "getRecipe() … Replaced in 1.21.2 with getRecipeId() / RecipeDisplayId".

This affects main (26.2) as well — the struct is unchanged.

Fix

Add a RecipeDisplayId VarInt newtype and use it in the packet. With the fix the same serialization
is 3 bytes ([0, 20, 1]), matching the server, and azalea-protocol compiles cleanly.

(Sending a specific recipe then needs the display id from the recipe book — a separate concern from
this serialization fix.)