chore: initial commit of Wagtail backend scaffold

apps/core/signals.py

@@ -0,0 +1,27 @@
+"""
+Wagtail signal handlers：发布内容后通知 Next.js 前端失效 ISR 缓存。
+详见 documents/设计方案分析与完善版.md §2.7。
+"""
+import logging
+
+import requests
+from django.conf import settings
+from django.dispatch import receiver
+from wagtail.signals import page_published
+
+logger = logging.getLogger(__name__)
+
+
+@receiver(page_published)
+def notify_frontend_revalidate(sender, instance, **kwargs):
+    if not settings.FRONTEND_REVALIDATE_URL:
+        return
+    try:
+        requests.post(
+            settings.FRONTEND_REVALIDATE_URL,
+            json={"tags": [f"page:{instance.id}", instance.url_path]},
+            headers={"Authorization": f"Bearer {settings.REVALIDATE_SECRET}"},
+            timeout=3,
+        )
+    except requests.RequestException:
+        logger.warning("Failed to notify frontend revalidate webhook", exc_info=True)