ci: Add daily snipsync GitHub workflow

.github/workflows/snipsync.yml

@@ -0,0 +1,83 @@
+name: Snipsync
+
+on:
+  schedule:
+    - cron: '0 6 * * *' # Daily at 6:00 UTC
+  workflow_dispatch:
+
+jobs:
+  snipsync:
+    name: Sync code snippets
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    steps:
+      - name: Generate token
+        id: generate_token
+        uses: actions/create-github-app-token@v1
+        with:
+          app-id: ${{ secrets.TEMPORAL_CICD_APP_ID }}
+          private-key: ${{ secrets.TEMPORAL_CICD_PRIVATE_KEY }}
+
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          token: ${{ steps.generate_token.outputs.token }}
+          ref: main
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: yarn
+
+      - name: Install dependencies
+        run: yarn install --frozen-lockfile
+
+      - name: Run snipsync
+        run: yarn snipsync
+
+      - name: Check for changes
+        id: changes
+        run: |
+          if git diff --quiet; then
+            echo "has_changes=false" >> "$GITHUB_OUTPUT"
+          else
+            echo "has_changes=true" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Commit and push changes
+        if: steps.changes.outputs.has_changes == 'true'
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+          branch_name="snipsync/daily-update"
+          git checkout -B "$branch_name"
+          git add docs/
+          git commit -m "chore: sync code snippets via snipsync"
+          git push --force-with-lease origin "$branch_name"
+
+      - name: Create or update PR
+        if: steps.changes.outputs.has_changes == 'true'
+        env:
+          GH_TOKEN: ${{ steps.generate_token.outputs.token }}
+        run: |
+          branch_name="snipsync/daily-update"
+          existing_pr=$(gh pr list --head "$branch_name" --state open --json number --jq '.[0].number')
+
+          if [ -n "$existing_pr" ]; then
+            echo "PR #$existing_pr already exists — updated with latest push."
+          else
+            gh pr create \
+              --title "chore: sync code snippets" \
+              --body "$(cat <<'EOF'
+          Automated daily sync of code snippets from source repositories via snipsync.
+
+          This PR was generated by the [Snipsync workflow](https://github.com/${{ github.repository }}/actions/workflows/snipsync.yml).
+          EOF
+              )" \
+              --head "$branch_name" \
+              --base "main"
+          fi