feat: add statsd and matomo tracking for signup and activation funnel (#13190)

* feat: add statsd and matomo tracking for signup and activation funnel

This commit adds observability to measure signup to email verification funnel rates:

1. Statsd counters (ol.account.created, ol.account.verify.success, and ol.account.verify.fail)
   to track raw signup events, activation success events, and activation failures.
2. Matomo trackEvent ('Account', 'RegistrationSuccess') and ('Account', 'ActivationSuccess')
   pushed via JavaScript so Matomo can capture device types natively from the User-Agent.

---------

Co-authored-by: Mek <michael.karpeles@gmail.com>

Author: Sadashii

openlibrary/plugins/upstream/account.py

@@ -692,6 +692,7 @@ def GET(self):
             raise web.seeother("/account/create")
         r = InternetArchiveAccount.verify(token=i.t)
         if "error" in r:
+            stats.increment("ol.account.verify.fail")
             if accounts.get_current_user():
                 raise web.seeother("/account/books")
             add_flash_message(
@@ -700,6 +701,8 @@ def GET(self):
             )
             raise web.seeother("/account/create")
         add_flash_message("success", _("Your email has been verified. You are now logged in."))
+        stats.increment("ol.account.verify.success")
+        web.setcookie("ol_activation", "1", expires=300)
         kwargs = {"access": r["s3"]["access"], "secret": r["s3"]["secret"]}
         if i.redirect:
             kwargs["redirect"] = i.redirect

openlibrary/templates/account/verify.html

@@ -15,3 +15,8 @@ <h1>$_("Hi, %(user)s", user=username)!</h1>
   </p>
 
 </div>
+
+<script>
+  var _paq = window._paq = window._paq || [];
+  _paq.push(['trackEvent', 'Account', 'RegistrationSuccess']);
+</script>

openlibrary/templates/site/head.html

@@ -63,6 +63,12 @@
    // Dimension 1 (visit-scoped): "Days Since Registration" — ID must match Matomo admin config (issue #12144)
    var _paq = window._paq = window._paq || [];
    _paq.push(['setCustomDimension', 1, $:json_encode(get_days_registered(ctx.user))]);
+   // One-shot ActivationSuccess: cookie set by /account/verify on successful email activation.
+   // Cleared immediately so it only fires once per activation.
+   if (document.cookie.match(/(?:^|;\s*)ol_activation=1/)) {
+     _paq.push(['trackEvent', 'Account', 'ActivationSuccess']);
+     document.cookie = 'ol_activation=; expires=Thu, 01 Jan 1970 00:00:00 GMT; path=/';
+   }
 
    var _mtm = window._mtm = window._mtm || [];
    _mtm.push({'mtm.startTime': (new Date().getTime()), 'event': 'mtm.Start'});