Fix Codex transcript convergence

app/androidApp/src/main/kotlin/com/example/aiapp/Events.kt

@@ -61,6 +61,9 @@ sealed class SessionEvent {
 
     data class AssistantText(val delta: String) : SessionEvent()
 
+    /** The durable value of the open assistant message, replacing its provisional deltas. */
+    data class AssistantTextFinal(val text: String) : SessionEvent()
+
     data class ToolStart(val id: String, val tool: String, val input: String) : SessionEvent()
 
     data class ToolUpdate(val id: String, val output: String) : SessionEvent()
@@ -225,6 +228,7 @@ fun parseSeqEvent(json: String): SeqEvent {
                 )
             "messageDropped" -> SessionEvent.MessageDropped(body.getString("id"))
             "assistantText" -> SessionEvent.AssistantText(body.getString("delta"))
+            "assistantTextFinal" -> SessionEvent.AssistantTextFinal(body.getString("text"))
             "toolStart" ->
                 SessionEvent.ToolStart(
                     id = body.getString("id"),