feat(notifications): per-chat mute settings

- add chat_notification_settings table and migration
- add chat notifications API (get/update muted)
- skip message notifications for muted recipients
- add mute/unmute control in chat info panel

app/notifications/service.py

@@ -3,7 +3,7 @@ import re
 
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.chats.repository import list_chat_members
+from app.chats.repository import is_chat_muted_for_user, list_chat_members
 from app.messages.models import Message
 from app.notifications.repository import create_notification_log, list_user_notifications
 from app.notifications.schemas import NotificationRead, NotificationRequest
@@ -44,6 +44,8 @@ async def dispatch_message_notifications(db: AsyncSession, message: Message) ->
     sender_name = sender_users[0].username if sender_users else "Someone"
 
     for recipient in users:
+        if await is_chat_muted_for_user(db, chat_id=message.chat_id, user_id=recipient.id):
+            continue
         base_payload = {
             "chat_id": message.chat_id,
             "message_id": message.id,