feat: protocol 767 (1.21) packet handling and AttributeSubComponent update

- Add AttributeSubComponent121 that uses ResourceLocation(string) instead
  of UUID+Name, matching the 1.21 attribute modifier wire format change.
  Register it in SubComponentRegistry121 via new ReplaceSubComponent method.
- Add ProjectilePower packet handler: reads 1 double (accelerationPower)
  for 1.21+, or 3 doubles (xPower/yPower/zPower) for 1.20.6.
- Add CustomReportDetails and ServerLinks packet handlers in both Play
  and Configuration phases, consuming all fields to prevent byte offset
  errors on 1.21 servers.

Made-with: Cursor

MinecraftClient/Protocol/Handlers/StructuredComponents/Registries/Subcomponents/SubComponentRegistry121.cs

@@ -10,6 +10,7 @@ public class SubComponentRegistry121 : SubComponentRegistry1206
 {
     public SubComponentRegistry121(DataTypes dataTypes) : base(dataTypes)
     {
+        ReplaceSubComponent<AttributeSubComponent121>(SubComponents.Attribute);
         RegisterSubComponent<SoundEventSubComponent>(SubComponents.SoundEvent);
     }
 }