feat(P5C.T2): per-conv 'mentions only' toggle + notification gate

apps/desktop/src/components/ConversationRowMenu.tsx

@@ -1,6 +1,7 @@
 import {
   muteDurationToIso,
   setConversationArchived,
+  setConversationMentionsOnly,
   setConversationMutedUntil,
 } from '@chat-app/shared/chat';
 import { forwardRef, useCallback, useEffect, useRef, useState } from 'react';
@@ -8,12 +9,13 @@ import { createPortal } from 'react-dom';
 import { useTranslation } from 'react-i18next';
 
 import { supabase } from '../lib/supabase';
-import { ArchiveIcon, BellIcon, BellOffIcon, MoreVerticalIcon } from './icons';
+import { ArchiveIcon, AtIcon, BellIcon, BellOffIcon, MoreVerticalIcon } from './icons';
 
 interface Props {
   conversationId: string;
   archived: boolean;
   mutedUntil: string | null;
+  mentionsOnly: boolean;
 }
 
 interface MuteOption {
@@ -50,7 +52,7 @@ interface MenuPos {
 // escape the sidebar's `overflow-y-auto` clipping context. Position is
 // computed from the trigger's bounding rect — menu anchors right-aligned
 // under the trigger so it doesn't push off-screen on narrow windows.
-export function ConversationRowMenu({ conversationId, archived, mutedUntil }: Props) {
+export function ConversationRowMenu({ conversationId, archived, mutedUntil, mentionsOnly }: Props) {
   const { t } = useTranslation(['app']);
   const [open, setOpen] = useState(false);
   const [submenuOpen, setSubmenuOpen] = useState<'mute' | null>(null);
@@ -145,6 +147,21 @@ export function ConversationRowMenu({ conversationId, archived, mutedUntil }: Pr
     [conversationId],
   );
 
+  const handleMentionsOnly = useCallback(
+    async (next: boolean) => {
+      setOpen(false);
+      try {
+        await setConversationMentionsOnly(supabase, {
+          conversationId,
+          mentionsOnly: next,
+        });
+      } catch (err: unknown) {
+        console.warn('mentions-only toggle failed', err);
+      }
+    },
+    [conversationId],
+  );
+
   return (
     <>
       <button
@@ -196,6 +213,16 @@ export function ConversationRowMenu({ conversationId, archived, mutedUntil }: Pr
               }}
               hasSubmenu={!isMuted}
             />
+            <MenuItem
+              icon={<AtIcon className="h-4 w-4" />}
+              label={
+                (mentionsOnly ? '✓ ' : '') +
+                t('app:chats.mentions_only', {
+                  defaultValue: 'Nur bei @Mentions benachrichtigen',
+                })
+              }
+              onClick={() => void handleMentionsOnly(!mentionsOnly)}
+            />
           </div>,
           document.body,
         )}

apps/desktop/src/context/ConversationsContext.tsx

@@ -225,7 +225,12 @@ export function ConversationsProvider({ children }: { children: ReactNode }) {
                 (c) => c.id === row.conversation_id,
               );
               const muted = isConversationMuted(convForMute?.mutedUntil ?? null);
-              if (presenceRef.current !== 'dnd' && !muted) {
+              // "Mentions only" silences non-mention messages here. Mentions
+              // still fire via the independent useMentionNotifications
+              // subscription on message_mentions, so this branch doesn't
+              // lose the @-alerts.
+              const mentionsOnly = convForMute?.mentionsOnly ?? false;
+              if (presenceRef.current !== 'dnd' && !muted && !mentionsOnly) {
                 playNotificationTone();
                 const conv = conversationsRef.current.find(
                   (c) => c.id === row.conversation_id,

apps/desktop/src/pages/ChatsPage.tsx

@@ -425,6 +425,7 @@ function ConversationRow({
         conversationId={item.id}
         archived={item.archived}
         mutedUntil={item.mutedUntil}
+        mentionsOnly={item.mentionsOnly}
       />
     </NavLink>
   );