Add CI

.github/workflows/ci.yml

@@ -0,0 +1,45 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - '*'
+  workflow_dispatch:
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  macos-26:
+    name: macOS
+    runs-on: macos-26
+    strategy:
+      matrix:
+        xcode:
+          - '26.2'
+    steps:
+      - uses: actions/checkout@v5
+      - name: Select Xcode ${{ matrix.xcode }}
+        run: sudo xcode-select -s /Applications/Xcode_${{ matrix.xcode }}.app
+      - name: Build
+        run: swift build
+
+  linux:
+    name: Linux
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        swift:
+          - '6.2.3'
+    steps:
+      - uses: actions/checkout@v5
+      - name: Install Swift ${{ matrix.swift }}
+        uses: swift-actions/setup-swift@v3
+        with:
+          swift-version: ${{ matrix.swift }}
+      - name: Build
+        run: swift build