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/middleware.py

@@ -1,10 +1,54 @@
+import logging
+
 from django.utils.crypto import get_random_string
 
-from analytics.models import Attribution, UTMVisit
+from analytics.models import Attribution, PageView, UTMVisit
 
 
+logger = logging.getLogger(__name__)
+
 CORRELATION_COOKIE = "ms_cid"
 
+# Portal, auth, health, assets, and transactional public endpoints.
+_SKIP_PREFIXES = (
+    "/portal/",
+    "/admin/",
+    "/accounts/",
+    "/api/",
+    "/healthz",
+    "/static/",
+    "/media/",
+    "/unsubscribe/",
+)
+_SKIP_PATHS = frozenset({"/robots.txt", "/sitemap.xml", "/favicon.ico"})
+
+
+class PublicPageViewMiddleware:
+    """Record successful GET hits on public marketing pages."""
+
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request):
+        response = self.get_response(request)
+        if _should_record_page_view(request, response):
+            try:
+                PageView.objects.create(path=request.path[:512])
+            except Exception:
+                logger.exception("Failed to record page view for %s", request.path)
+        return response
+
+
+def _should_record_page_view(request, response) -> bool:
+    if request.method != "GET":
+        return False
+    if getattr(response, "status_code", 0) != 200:
+        return False
+    path = request.path
+    if path in _SKIP_PATHS:
+        return False
+    return not any(path.startswith(prefix) for prefix in _SKIP_PREFIXES)
+
 
 class UTMTrackingMiddleware:
     """Capture UTM params into UTMVisit and stash a correlation id cookie."""