🐛 Report throttled update loops as unhandled exceptions

The throttled update loop report used the handled-exception event, which
only lands in the audit log: error reports and alerts read
unhandled-exception and exception-page. A throttled loop is an
application defect (its cause has :type :internal), and the point of the
report is to find those loops, so it is now an unhandled exception.

AI-assisted-by: claude-opus-5-5

frontend/src/app/main/errors.cljs

@@ -438,10 +438,10 @@
   (volatile! 0))
 
 (defn on-update-loop
-  "Handler for the rumext update scheduler trips: logs and reports the
-  throttled update loop with the events being processed, at most once per
-  `report-window-ms`. Runs inside store watchers and effect bodies, so it
-  never throws."
+  "Handler for the rumext update scheduler trips: logs the throttled
+  update loop and reports it as an unhandled exception with the events
+  being processed, at most once per `report-window-ms`. Runs inside store
+  watchers and effect bodies, so it never throws."
   [{:keys [rounds]}]
   (try
     (let [now (inst-ms (ct/now))]
@@ -456,9 +456,11 @@
                  (into-array (map ptk/repr-event events)))
           (when (seq events)
             (.set in-flight-by-cause cause (in-flight-lines events)))
-          ;; Report outside the loop that tripped the scheduler
+          ;; Report outside the loop that tripped the scheduler, as an
+          ;; unhandled exception: a throttled loop is an application defect,
+          ;; so it must reach the error reports and alerts, not only audit.
           (ts/schedule
-           #(submit-report :event-name "handled-exception"
+           #(submit-report :event-name "unhandled-exception"
                            :hint (ex-message cause)
                            :report (fn [] (generate-report cause))
                            :cause cause)))))

frontend/test/frontend_tests/main_errors_test.cljs

@@ -15,7 +15,7 @@
       store was processing when it caught the exception; a failing stream
       pipeline lists the emitters of the value, not its own event
     - on-update-loop              – never throws into the scheduler's caller;
-      reports the throttled loop with the events in flight
+      reports the throttled loop as unhandled, with the events in flight
     - flash schedules async report and toast – neither the report nor
       ntf/show is emitted synchronously
     - organization SSO recovery   – expired SSO sessions go back to the provider
@@ -572,7 +572,9 @@
        (errors/on-update-loop {:rounds 26})
        (t/is (= 1 (count @events)))
        (let [props (deref (first @events))]
-         (t/is (= "handled-exception" (::ev/name props)))
+         ;; An unhandled report: it reaches the error reports and alerts,
+         ;; not only the audit log.
+         (t/is (= "unhandled-exception" (::ev/name props)))
          (t/is (= "update loop throttled" (:hint props)))
          (t/is (str/includes? (in-flight-section (:report props))
                               "test-update-loop-source")))))))