Four tiers per brand: RZX 60/70/80/90 and RZ 70/80/800/900

Model name is display only; performance and price follow brand and tier.
Tier physical traits: power pins 6/8/8/8+8 and fans 1/2/3/3.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/Decentralized/Unlock.cs

@@ -32,7 +32,7 @@ namespace Decentralized
         {
             Items.Give(ModHelper.SpawnItem(Items.Terminal));
             Items.Give(ModHelper.SpawnItem(Items.Rig));
-            Items.Give(ModHelper.SpawnItem(Items.GpuId("RZX50")));
+            Items.Give(ModHelper.SpawnItem(Items.GpuId("RZX60")));
             Log.Info("已加入 Web3 治理社区");
         }
     }