Add CI actions.

Author: blakerouse

.github/workflows/ci.yml

@@ -0,0 +1,41 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Go
+      uses: actions/setup-go@v5
+      with:
+        go-version: '1.24'
+
+    - name: Verify formatting
+      run: |
+        if [ "$(gofmt -l . | wc -l)" -gt 0 ]; then
+          echo "Please run gofmt"
+          gofmt -l .
+          exit 1
+        fi
+
+    - name: Verify go mod
+      run: |
+        go mod verify
+        go mod tidy
+        git diff --exit-code go.mod go.sum
+
+    - name: Run go vet
+      run: go vet ./...
+
+    - name: Run tests
+      run: go test -v -race ./...
+
+    - name: Build
+      run: go build .