feat: complete saleor core extensions app with React email templates

- Order confirmation, shipped, and cancelled email templates
- Uses @react-email/components for professional HTML emails
- Sends admin and customer notifications
- Integrates with Resend for email delivery
- Webhook handlers for ORDER_CREATED, ORDER_FULFILLED, ORDER_CANCELLED
- Docker image optimized for production
- Persistent auth data storage via PVC

.github/workflows/assign-pr.yml

@@ -0,0 +1,16 @@
+name: Assign PR to creator
+
+on:
+  pull_request:
+    types: [opened]
+
+jobs:
+  assign_creator:
+    runs-on: ubuntu-22.04
+    permissions:
+      pull-requests: write
+    steps:
+      - name: Assign PR to creator
+        uses: toshimaru/auto-author-assign@ebd30f10fb56e46eb0759a14951f36991426fed0 # v2.1.0
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}