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/analytics.ex

@@ -364,6 +364,20 @@ defmodule Berrypod.Analytics do
     |> Repo.all()
   end
 
+  @doc """
+  Counts all-time pageviews for a specific path.
+
+  Used by the broken URL tracker to distinguish real broken URLs
+  (paths that previously had traffic) from bot noise.
+  """
+  def count_pageviews_for_path(path) do
+    from(e in Event,
+      where: e.name == "pageview" and e.pathname == ^path,
+      select: count()
+    )
+    |> Repo.one()
+  end
+
   @doc """
   Deletes events older than the given datetime. Used by the retention worker.
   """

lib/berrypod/redirects.ex

@@ -336,6 +336,44 @@ defmodule Berrypod.Redirects do
     Repo.one(from b in BrokenUrl, where: b.path == ^path and b.status == "pending")
   end
 
+  # ── Auto-resolve ──
+
+  @doc """
+  Attempts to auto-resolve a broken product URL using FTS5 search.
+
+  Converts the slug back to words and searches the product index.
+  If exactly one result is found, creates a redirect and marks
+  the broken URL as resolved. Multiple or zero results are left
+  for admin review.
+  """
+  def attempt_auto_resolve("/products/" <> old_slug = path) do
+    query = old_slug |> String.replace("-", " ") |> String.trim()
+
+    case Berrypod.Search.search(query) do
+      [%{slug: new_slug}] when new_slug != old_slug ->
+        case create_auto(%{
+               from_path: path,
+               to_path: "/products/#{new_slug}",
+               source: "analytics_auto_resolved"
+             }) do
+          {:ok, _redirect} ->
+            if broken = get_broken_url_by_path(path) do
+              mark_broken_url_resolved(broken)
+            end
+
+            :resolved
+
+          _error ->
+            :no_match
+        end
+
+      _ ->
+        :no_match
+    end
+  end
+
+  def attempt_auto_resolve(_path), do: :no_match
+
   # ── Pruning ──
 
   @doc """

lib/berrypod/redirects/redirect.ex

@@ -5,7 +5,7 @@ defmodule Berrypod.Redirects.Redirect do
   @primary_key {:id, :binary_id, autogenerate: true}
   @foreign_key_type :binary_id
 
-  @sources ~w(auto_slug_change auto_product_deleted analytics_detected admin)
+  @sources ~w(auto_slug_change auto_product_deleted analytics_auto_resolved admin)
 
   schema "redirects" do
     field :from_path, :string

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__