ci: build and test on Windows for every pull request

Server 端此前没有 CI。tests/ 下已有几十个测试文件并通过 add_test 注册，但从来没有在 PR 上跑过，回归只能靠人工在本机复现。

workflow 不走 preset：preset 指定 Visual Studio 18 2026 生成器和 C:/Users/sonnycalcr 的 vcpkg 路径，在 runner 上都不成立。Boost 也不能来自 manifest——CMakeLists.txt 要求 Boost locale 和 json 且按静态链接，但 vcpkg.json 里没有声明它，README 让用 Scoop 单独安装。这里改用 classic 模式装静态 Boost，再通过 CMakeLists.txt 已经支持的 BOOST_ROOT 环境变量指过去，不改动 vcpkg.json。

server/.github/workflows/ci.yml

@@ -0,0 +1,42 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    name: Windows x64
+    runs-on: windows-2025
+    steps:
+      - name: Check out source
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
+        with:
+          submodules: recursive
+      - name: Install Boost
+        shell: pwsh
+        # CMakeLists.txt links Boost statically but does not declare it in
+        # vcpkg.json, so it cannot come from the manifest. Install it in classic
+        # mode from the vcpkg installation root and point BOOST_ROOT at it, which
+        # is the override CMakeLists.txt already supports.
+        run: |
+          Push-Location $env:VCPKG_INSTALLATION_ROOT
+          ./vcpkg install boost-locale:x64-windows-static boost-json:x64-windows-static
+          Pop-Location
+          "BOOST_ROOT=$env:VCPKG_INSTALLATION_ROOT/installed/x64-windows-static" >> $env:GITHUB_ENV
+      - name: Configure
+        shell: pwsh
+        run: >
+          cmake -S . -B build -A x64
+          -DCMAKE_TOOLCHAIN_FILE="$env:VCPKG_INSTALLATION_ROOT/scripts/buildsystems/vcpkg.cmake"
+          -DVCPKG_TARGET_TRIPLET=x64-windows
+      - name: Build
+        shell: pwsh
+        run: cmake --build build --config Release --parallel
+      - name: Test
+        shell: pwsh
+        run: ctest --test-dir build -C Release --output-on-failure --timeout 120