Add GitHub Actions CI workflow

.github/workflows/ci.yml

@@ -0,0 +1,42 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+    tags: ["v*"]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Setup .NET 8
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 8.0.x
+
+      - name: Install Cake.Tool
+        run: dotnet tool install --global Cake.Tool
+
+      - name: Run Cake Build
+        run: dotnet cake build.cake --target=Test
+
+      - name: Upload build artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: build-output
+          path: build/
+
+      - name: Create Release (tag only)
+        if: startsWith(github.ref, 'refs/tags/v')
+        uses: softprops/action-gh-release@v2
+        with:
+          files: build/*
+          generate_release_notes: true