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/samples/ExamplePlugin/NuGet.Config

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <clear />
+    <!-- Repository sample consumes the packages produced by GameSdk/Pack.ps1. -->
+    <add key="bd2-local" value="../../../../.build/nuget" />
+    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+</configuration>