Add GitHub workflows

.github/workflows/ci.yml

@@ -0,0 +1,55 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+    paths-ignore:
+      - '**.md'
+      - 'LICENSE*'
+      - '.gitignore'
+      - '.editorconfig'
+      - '**.gif'
+      - '**.png'
+      - '**.jpg'
+  pull_request:
+    branches:
+      - '*'
+    paths-ignore:
+      - '**.md'
+      - 'LICENSE*'
+      - '.gitignore'
+      - '.editorconfig'
+      - '**.gif'
+      - '**.png'
+      - '**.jpg'
+  workflow_dispatch:
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Test All Platforms
+    runs-on: macos-15
+    steps:
+      - uses: actions/checkout@v4
+      - name: Select Xcode 26.0
+        run: sudo xcode-select -s /Applications/Xcode_26.0.app
+      - name: Skip macro validation
+        run: defaults write com.apple.dt.Xcode IDESkipMacroFingerprintValidation -bool YES
+      - name: Run tests
+        run: make test
+
+  backward-compatibility:
+    name: Backward Compatibility (Xcode 16.4)
+    runs-on: macos-15
+    steps:
+      - uses: actions/checkout@v4
+      - name: Select Xcode 16.4
+        run: sudo xcode-select -s /Applications/Xcode_16.4.app
+      - name: Skip macro validation
+        run: defaults write com.apple.dt.Xcode IDESkipMacroFingerprintValidation -bool YES
+      - name: Test macOS
+        run: make test-macos