Add Windows CI build

.github/workflows/build.yml

@@ -0,0 +1,52 @@
+name: Build
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  windows:
+    runs-on: windows-latest
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Cache Qt5
+        uses: actions/cache@v4
+        with:
+          path: build/_deps
+          key: qt5-msvc2017-x64-${{ hashFiles('cmake/FindQt5.cmake') }}
+
+      - uses: ilammy/msvc-dev-cmd@v1
+        with:
+          arch: x64
+
+      - name: Configure
+        run: cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
+
+      - name: Build
+        run: cmake --build build
+
+      - name: Test
+        run: ctest --test-dir build --output-on-failure
+
+      - name: Upload build
+        uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: Reclass-Windows-x64
+          path: |
+            build/Reclass.exe
+            build/ReclassMcpBridge.exe
+            build/Plugins/
+            build/*.dll
+            build/platforms/
+            build/styles/
+            build/imageformats/
+            build/iconengines/
+            build/themes/
+            build/screenshot.png