feat(notifications): include public chat mentions in feed

Add ChannelMessageEvent.KIND (NIP-28 kind 42) to the Notifications feed's
allow-list so channel messages that p-tag the user surface in the in-app
Notifications screen, alongside text-note mentions and DMs.

The relay subscription already requests kind 42 with #p (see
FilterNotificationsToPubkey.NotificationsPerKeyKinds), and push notifications
already route ChannelMessageEvent through notifyMention. Only the in-app
feed filter was rejecting them at the kind check; the existing
tagsAnEventByUser gate handles the per-kind "is this for me" rule via the
BaseNoteEvent branch (reply-to-me, cited-author, citation-in-content).

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/notifications/dal/NotificationFeedFilter.kt

@@ -49,6 +49,7 @@ import com.vitorpamplona.quartz.nip18Reposts.RepostEvent
 import com.vitorpamplona.quartz.nip22Comments.CommentEvent
 import com.vitorpamplona.quartz.nip23LongContent.LongTextNoteEvent
 import com.vitorpamplona.quartz.nip25Reactions.ReactionEvent
+import com.vitorpamplona.quartz.nip28PublicChat.message.ChannelMessageEvent
 import com.vitorpamplona.quartz.nip34Git.issue.GitIssueEvent
 import com.vitorpamplona.quartz.nip34Git.patch.GitPatchEvent
 import com.vitorpamplona.quartz.nip52Calendar.appt.day.CalendarDateSlotEvent
@@ -111,6 +112,7 @@ class NotificationFeedFilter(
         val NOTIFICATION_KINDS =
             setOf(
                 BadgeAwardEvent.KIND,
+                ChannelMessageEvent.KIND,
                 ChatMessageEvent.KIND,
                 ChatMessageEncryptedFileHeaderEvent.KIND,
                 CommentEvent.KIND,