skip Memory entries in conversation replay on restore

Memory entries (surfaced nodes, memory_render results) are part of
the context window but not the conversation display. Skip them
during replay_session_to_ui to avoid showing system-reminder
content as user messages.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/bin/poc-agent.rs

@@ -1063,6 +1063,8 @@ fn replay_session_to_ui(entries: &[types::ConversationEntry], ui_tx: &ui_channel
     let mut target = StreamTarget::Conversation;
 
     for entry in entries {
+        // Memory entries are in the context window but not the conversation display
+        if entry.is_memory() { continue; }
         let msg = entry.message();
         match msg.role {
             types::Role::System => {}