fix(gui): Windows 构建链改用 modelrouter 命名 + 内嵌核心 strip

改名在桌面打包链上漏了两处，都是"构建能过、产物不可用"的类型：

1. `dist-win-docker.sh` 仍交叉编译到 `bin/llmsproxy.exe` 并构建
   `./cmd/llmsproxy`，而 package.json 的 extraResources 已指向
   `bin/modelrouter.exe` —— Windows 包装完会缺内嵌核心。
   同时把 npmmirror 的 electron / electron-builder-binaries 镜像传进容器：
   首次构建需在容器内下载数百 MB，直连会卡满 600s 请求超时（Linux 侧已实测）。

2. `prepare-core.js` 只带 `-trimpath`，内嵌核心保留调试符号（14.4MB）。
   补 `-ldflags "-s -w"`，与 `packaging/core-dist.sh` 一致，各平台安装包少约 4MB。

cmd/gui/scripts/prepare-core.js

@@ -17,7 +17,10 @@ function buildLinux() {
   fs.mkdirSync(binDir, { recursive: true });
   execFileSync(
     "go",
-    ["build", "-tags", "luajit", "-trimpath", "-o", out, "./cmd/modelrouter"],
+    // -s -w: same stripping as packaging/core-dist.sh. Without it the bundled
+    // core carries debug info (~14.4 MB vs ~10.3 MB) and every installer pays
+    // for it, for a binary the user never debugs.
+    ["build", "-tags", "luajit", "-trimpath", "-ldflags", "-s -w", "-o", out, "./cmd/modelrouter"],
     { cwd: projectRoot, stdio: "inherit" },
   );
   return out;
@@ -43,7 +46,7 @@ function buildWin() {
   }
   execFileSync(
     "go",
-    ["build", "-tags", "luajit", "-trimpath", "-o", out, "./cmd/modelrouter"],
+    ["build", "-tags", "luajit", "-trimpath", "-ldflags", "-s -w", "-o", out, "./cmd/modelrouter"],
     {
       cwd: projectRoot,
       stdio: "inherit",