Add more run optns and don't run Windows for PRs

.github/workflows/smoke.yaml

@@ -1,7 +1,11 @@
 name: smoke
 
 on:
+  push:
+    branches: [ main ]
   pull_request:
+  schedule: # midnight every day
+    - cron:  '0 0 * * *'
   workflow_dispatch:
 
 jobs:
@@ -10,6 +14,13 @@ jobs:
     strategy:
       matrix:
         os: [windows-latest, ubuntu-latest]
+    env:
+      BASE_REPO: ${{ github.repository }}
+      BRANCH: ${{ github.head_ref }}
+      PR_REPO: ${{ github.event.pull_request.head.repo.full_name }}
+      SHA: ${{ github.sha }}
+    # TODO: drop PR testing under Windows because it's too slow?
+    # if: github.event_name != 'pull_request' && matrix.os != 'windows-latest'
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
@@ -19,11 +30,15 @@ jobs:
           cache-dependency-path: package.json
       - run: tools/install-hugo.sh
         shell: bash
-      - name: Make site
-        env:
-          REPO: ${{ github.event.pull_request.head.repo.full_name }}
-          BRANCH: ${{ github.head_ref }}
+      - name: Make site (non-PR)
+        if: github.event_name != 'pull_request'
         run: |
           mkdir tmp && cd tmp && set -x
-          ../tools/make-site.sh -p $REPO -v $BRANCH
+          ../tools/make-site.sh -p $BASE_REPO -v $SHA
+        shell: bash
+      - name: Make site from PR
+        if: github.event_name == 'pull_request'
+        run: |
+          mkdir tmp && cd tmp && set -x
+          ../tools/make-site.sh -p $PR_REPO -v $BRANCH
         shell: bash