Add public PageView tracking for portal analytics (#4)

## Summary
Closes #3.

- Add `PageView` model + migration for successful public marketing GET hits
- Wire `PublicPageViewMiddleware` (skips portal/admin/accounts/api/static/health/etc.; fails soft on DB errors)
- Portal analytics report: last-30-day views + top pages table
- Admin registration and tests

## Test plan
- [ ] Apply migration `analytics.0002_pageview`
- [ ] Hit `/` and `/about/` → rows in `PageView` / admin
- [ ] Hit `/healthz/`, `/portal/`, `/admin/` → no new pageviews
- [ ] Open portal Analytics → views count + Top pages look right
- [ ] `uv run python site/manage.py test analytics.tests`

Reviewed-on: #4

site/analytics/views.py

@@ -5,7 +5,7 @@ from django.db.models import Count
 from django.shortcuts import render
 from django.utils import timezone
 
-from analytics.models import Attribution, UTMVisit
+from analytics.models import Attribution, PageView, UTMVisit
 
 
 def _bar_pct(rows, key="count"):
@@ -18,7 +18,11 @@ def _bar_pct(rows, key="count"):
 @login_required
 def report(request):
     since_30d = timezone.now() - timedelta(days=30)
-    visits_last_30_days = UTMVisit.objects.filter(created_at__gte=since_30d).count()
+    pageviews_qs = PageView.objects.filter(created_at__gte=since_30d)
+    pageviews_last_30_days = pageviews_qs.count()
+    top_pages = list(
+        pageviews_qs.values("path").annotate(count=Count("id")).order_by("-count")[:20]
+    )
 
     visits_by_source = _bar_pct(
         list(
@@ -60,7 +64,8 @@ def report(request):
         request,
         "analytics/report.html",
         {
-            "visits_last_30_days": visits_last_30_days,
+            "pageviews_last_30_days": pageviews_last_30_days,
+            "top_pages": top_pages,
             "total_visits": UTMVisit.objects.count(),
             "total_attributed": Attribution.objects.count(),
             "top_source": (top_visit or {}).get("utm_source") or "(direct)",