feat(all): add game SDK and harden client login and game rules

- Add costume burst upgrades with durable replay and fix permanent SR equipment gacha.
- Add server game.json rules for optional collaboration UR weapons, with packaging and documentation.
- Add GameNames/GameSdk NuGet tooling, readable types, reobfuscation, complete source/PDB navigation and shared-runtime installation.
- Split plugin responsibilities, prefer typeof/nameof, centralize MSBuild settings and ignore local paths; remove the unused LoginUI test project.
- Fix login recovery and TLS through native platform HTTP and a private game relay; read device region directly from the OS time zone.

Validation: go test ./... -count=1, go vet ./..., plugin Release builds, SDK/runtime self-tests, Roslyn embedded-source navigation, gofmt check and git diff --check.

plugins/GameSdk/GameSdk.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <Import Project="../PackageMetadata.props" />
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>disable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+  <ItemGroup>
+    <PackageReference Include="ICSharpCode.Decompiler" Version="9.1.0.7988" />
+    <PackageReference Include="Mono.Cecil" Version="0.11.6" />
+    <Compile Include="../GameNames/NameTable.cs" Link="NameTable.cs" />
+    <Compile Remove="samples/**/*.cs;Package/**/*.cs" />
+    <EmbeddedResource Include="../GameNames/Mappings/names.json.gz" LogicalName="BD2.GameNames.names.json.gz" />
+  </ItemGroup>
+</Project>