fix: stop nutzaps from rendering twice in the notification feed

NutzapEvent was missing from the textNoteCards exclusion filter in
convertToCard, so every nutzap was both grouped into the MultiSetCard /
NutzapUserSetCard path AND fell through to a standalone NoteCard, which
renders kind 9321 as a big RenderNutzap card. The result was a duplicate:
the same nutzap appeared once in the grouped card and once as an
individual note — the way a reply would.

LnZapEvent is already excluded for exactly this reason; nutzaps were
simply overlooked when the nutzap grouping was added. Exclude NutzapEvent
too so it only renders through the grouped path.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01X8ZruubvykNhfmrJXJA8s7

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

@@ -358,7 +358,13 @@ class CardFeedContentState(
                     it.event !is ReactionEvent &&
                         it.event !is RepostEvent &&
                         it.event !is GenericRepostEvent &&
-                        it.event !is LnZapEvent
+                        it.event !is LnZapEvent &&
+                        // Nutzaps are already grouped into nutzapsPerEvent (MultiSetCard)
+                        // or nutzapsPerUser (NutzapUserSetCard) above, exactly like lightning
+                        // zaps. Without this exclusion a nutzap would ALSO fall through to a
+                        // standalone NoteCard and render a second time as a big RenderNutzap
+                        // card — a duplicate of the grouped one.
+                        it.event !is NutzapEvent
                 }.map {
                     if (it.event is PrivateDmEvent || it.event is NIP17Group || it.isInMarmotGroup()) {
                         MessageSetCard(it)