✨ feat(native-planning): 添加 Rust ICSP 原生规划核心及 C# 互操作集成

* 新增 Rust 原生 ICSP 规划库 (Cargo 项目, CubicSpline 算法, FFI 接口)
* 新增 Flyshot.Native.Planning C# 互操作项目 (P/Invoke 封装)
* 更新 ControllerClientCompat 适配新的规划接口
* 添加构建脚本 (Copy-NativePlanningArtifacts.ps1)
* 新增互操作测试及一致性对比测试
* 更新解决方案文件和设计文档

src/Flyshot.Native.Planning/Flyshot.Native.Planning.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Flyshot.Core.Domain\Flyshot.Core.Domain.csproj" />
+    <ProjectReference Include="..\Flyshot.Core.Planning\Flyshot.Core.Planning.csproj" />
+  </ItemGroup>
+
+</Project>