feat: 项目初始化 + 3D方块世界原型 + AI助搭系统

初始化 monorepo: Go后端(7微服务) + Unity客户端(9模块) + 启动器

HTML5原型: Three.js 3D体素世界, Perlin噪声地形, 原版材质, 22种方块

Minecraft创造模式背包: 双栏布局, 拖拽移动物品, 方向性元件引脚

AI助搭策划文档 + 客户端/服务端骨架 + Docker Compose + CI

launcher/PCL-CE/Plain Craft Launcher 2.slnx

@@ -0,0 +1,17 @@
+<Solution>
+  <Configurations>
+    <BuildType Name="CI" />
+    <BuildType Name="Beta" />
+    <BuildType Name="Debug" />
+    <BuildType Name="Release" />
+    <Platform Name="AnyCPU" />
+    <Platform Name="ARM64" />
+    <Platform Name="x64" />
+  </Configurations>
+  <Project Path="PCL.Core\PCL.Core.csproj" Type="C#" />
+  <Project Path="PCL.Core.SourceGenerators\PCL.Core.SourceGenerators.csproj" Type="C#" />
+  <Project Path="PCL.Core.Test\PCL.Core.Test.csproj" Type="C#">
+    <Build Solution="*|*" Project="false" />
+    </Project>
+    <Project Path="Plain Craft Launcher 2\Plain Craft Launcher 2.csproj" Type="C#" />
+</Solution>