🐛(frontend) treat client-initiated connect aborts as events

`connect()` calls can be aborted by a `disconnect()` before the
join completes — typically when the user leaves, refreshes,
navigates away early, or when the component remounts. This is
expected behavior, not a failure.

Stop reporting these as errors. Track them as analytics events
instead, so we can still monitor their volume without polluting
error dashboards.

Volume is relatively low, but keeping visibility helps troubleshoot
users who complain about difficulty connecting to a room, and could
also flag a component that is re-rendering and killing the
connection.

src/frontend/src/features/rooms/components/Conference.tsx

@@ -6,6 +6,8 @@ import {
   usePersistentUserChoices,
 } from '@livekit/components-react'
 import {
+  ConnectionError,
+  ConnectionErrorReason,
   DisconnectReason,
   MediaDeviceFailure,
   Room,
@@ -25,7 +27,11 @@ import { VideoConference } from '../livekit/prefabs/VideoConference'
 import { css } from '@/styled-system/css'
 import { BackgroundProcessorFactory } from '../livekit/components/blur'
 import { LocalUserChoices } from '@/stores/userChoices'
-import { captureMediaEvent, reportError } from '@/features/analytics/telemetry'
+import {
+  captureEvent,
+  captureMediaEvent,
+  reportError,
+} from '@/features/analytics/telemetry'
 import { useConfig } from '@/api/useConfig'
 import { isFireFox } from '@/utils/livekit'
 import { useIsMobile } from '@/utils/useIsMobile'
@@ -227,6 +233,16 @@ export const Conference = ({
           onError={(e) => {
             const failure = MediaDeviceFailure.getFailure(e)
             if (failure && failure !== MediaDeviceFailure.Other) return
+
+            // connect() was aborted by a disconnect() before the join completed
+            if (
+              e instanceof ConnectionError &&
+              e.reason === ConnectionErrorReason.Cancelled
+            ) {
+              void captureEvent('connection-cancelled')
+              return
+            }
+
             reportError('livekit_room_error', e, {
               path: 'connect_publish',
             })