ci(go): scaffold workflow for PR triggers

Bare workflow file so GitHub recognizes it on pull_request events.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: nodeselector

.github/workflows/ci.yml

@@ -0,0 +1,36 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+jobs:
+  go:
+    name: Go
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        go-version: ['1.19', '1.22', '1.23']
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version: ${{ matrix.go-version }}
+
+      - name: Generate
+        run: make generate
+
+      - name: Verify no drift
+        run: git diff --exit-code go/pkg/lockfile/schema_gen.go
+
+      - name: Lint
+        run: make lint
+
+      - name: Test
+        run: make test