add analytics-powered 404 monitoring with FTS5 auto-resolve

BrokenUrlTracker now queries real analytics pageview counts instead of
hardcoding 0, so broken URLs with prior traffic are distinguished from
bot noise. For /products/ 404s with a single FTS5 search match, auto-
creates a redirect and marks the broken URL resolved. 1232 tests.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/berrypod_web/plugs/broken_url_tracker.ex

@@ -20,7 +20,12 @@ defmodule BerrypodWeb.Plugs.BrokenUrlTracker do
   rescue
     e in Phoenix.Router.NoRouteError ->
       unless static_path?(conn.request_path) do
-        Berrypod.Redirects.record_broken_url(conn.request_path, 0)
+        prior_hits = Berrypod.Analytics.count_pageviews_for_path(conn.request_path)
+        Berrypod.Redirects.record_broken_url(conn.request_path, prior_hits)
+
+        if prior_hits > 0 do
+          Berrypod.Redirects.attempt_auto_resolve(conn.request_path)
+        end
       end
 
       reraise e, __STACKTRACE__