feat(notifications): rebuild the group summary from the child's real MessagingStyle

The summary previously reconstructed each line from EXTRA_TITLE/EXTRA_TEXT, so
it showed the conversation title as the "sender". Extract the child's
MessagingStyle (public compat API) and reuse its latest message — real sender
Person and timestamp — falling back to the extras for children without an
extractable style.

Reimplements the useful half of an errored Copilot session's partial commit
(dropped from the branch): that version used the restricted
Message.getMessagesFromBundleArray API and also demoted fresh reactions on
already-read messages to historic context, which would have buried the very
event a reaction notification exists to surface.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: jamesarich

core/service/src/androidHostTest/kotlin/org/meshtastic/core/service/MeshNotificationManagerImplConversationTest.kt

@@ -182,6 +182,13 @@ class MeshNotificationManagerImplConversationTest {
 
         val summary = activeByTag("message_summary").single().notification
         assertEquals(Notification.GROUP_ALERT_CHILDREN, summary.groupAlertBehavior)
+        // The summary line is rebuilt from the child's real MessagingStyle, so it carries the actual sender.
+        val summaryLatest =
+            androidx.core.app.NotificationCompat.MessagingStyle.extractMessagingStyleFromNotification(summary)
+                ?.messages
+                ?.lastOrNull()
+        assertEquals("hello", summaryLatest?.text?.toString())
+        assertEquals("Hawk Ridge", summaryLatest?.person?.name?.toString())
 
         manager.cancelMessageNotification("0^all")
 

core/service/src/androidMain/kotlin/org/meshtastic/core/service/MeshNotificationManagerImpl.kt

@@ -523,15 +523,22 @@ class MeshNotificationManagerImpl(
                 .setConversationTitle(getString(Res.string.meshtastic_app_name))
 
         activeNotifications.forEach { sbn ->
-            val senderTitle = sbn.notification.extras.getCharSequence(Notification.EXTRA_TITLE)
-            val messageText = sbn.notification.extras.getCharSequence(Notification.EXTRA_TEXT)
-            val postTime = sbn.postTime
-
-            if (senderTitle != null && messageText != null) {
-                // For the summary, we're creating a generic Person for the sender from the active notification's title.
-                // We don't have the original Person object or its colors/ID, so we're just using the name.
-                val senderPerson = Person.Builder().setName(senderTitle).build()
-                messagingStyle.addMessage(messageText, postTime, senderPerson)
+            // Prefer the child's real MessagingStyle: its latest message carries the actual sender (Person, icon) and
+            // timestamp, so the summary line reads "Hawk Ridge: …" rather than the conversation title.
+            val latest =
+                NotificationCompat.MessagingStyle.extractMessagingStyleFromNotification(sbn.notification)
+                    ?.messages
+                    ?.lastOrNull()
+            if (latest?.text != null) {
+                val senderPerson = latest.person ?: Person.Builder().setName(getString(Res.string.you)).build()
+                messagingStyle.addMessage(latest.text, latest.timestamp, senderPerson)
+            } else {
+                // Fallback for children without an extractable style: rebuild a generic line from the extras.
+                val senderTitle = sbn.notification.extras.getCharSequence(Notification.EXTRA_TITLE)
+                val messageText = sbn.notification.extras.getCharSequence(Notification.EXTRA_TEXT)
+                if (senderTitle != null && messageText != null) {
+                    messagingStyle.addMessage(messageText, sbn.postTime, Person.Builder().setName(senderTitle).build())
+                }
             }
         }