Fix group chat push notifications rendering as direct messages on iOS

iOS classifies Communication Notifications as either MessagingDirect or
MessagingGroup based on recipient count on the INSendMessageIntent. Our
push payload omits the recipient list, so iOS sees zero recipients and
falls back to MessagingDirect, ignoring speakableGroupName.

Use INSendMessageIntentDonationMetadata.recipientCount with the new
convoMemberCount field from the chat service to tell iOS the conversation
has multiple participants. Apple documents this as the supported escape
hatch when the full recipient list is too large to ship.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

modules/BlueskyNSE/NotificationService.swift

@@ -120,6 +120,19 @@ class NotificationService: UNNotificationServiceExtension {
       attachments: nil
     )
 
+    // The push payload omits the full recipient list for group convos. Without
+    // any signal of multiple recipients, iOS classifies the notification as
+    // `MessagingDirect` and ignores `speakableGroupName`. Setting
+    // `recipientCount` on the donation metadata is Apple's documented escape
+    // hatch for this case, and overrides the (zero-length) recipients array.
+    if userInfo["convoKind"] as? String == "group",
+       let convoMemberCount = userInfo["convoMemberCount"] as? Int,
+       convoMemberCount > 0 {
+      let metadata = INSendMessageIntentDonationMetadata()
+      metadata.recipientCount = convoMemberCount
+      intent.donationMetadata = metadata
+    }
+
     // For group convos, attach the composite group avatar (rendered by the
     // ogcard service) to the `speakableGroupName` parameter so iOS shows it
     // alongside the sender on the Communication Notification.