ci: add Go validation workflow

.github/workflows/ci.yml

@@ -0,0 +1,61 @@
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Go / ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+          - macos-latest
+
+    steps:
+      - name: Check out
+        uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+          cache-dependency-path: go.sum
+
+      - name: Download modules
+        run: go mod download
+
+      - name: Check module tidiness
+        run: |
+          go mod tidy
+          git diff --exit-code -- go.mod go.sum
+
+      - name: Check formatting
+        run: |
+          unformatted="$(gofmt -l .)"
+          if [ -n "$unformatted" ]; then
+            echo "$unformatted"
+            exit 1
+          fi
+
+      - name: Vet
+        run: go vet ./...
+
+      - name: Test
+        run: go test ./...
+
+      - name: Build
+        run: go build -ldflags "-X github.com/openclaw/gitcrawl/internal/cli.version=${GITHUB_SHA:0:7}" -o bin/gitcrawl ./cmd/gitcrawl