fix: revert broken auto-merge of 266 in bot.rs

The mergemaster's auto-resolver inserted a duplicate chat_stream call
inside the tokio::select! permission loop, producing mismatched braces.
The 266 merge didn't contribute useful code changes to bot.rs — the
session_id handling was already present.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/matrix/bot.rs

@@ -818,20 +818,6 @@ async fn handle_message(
                     .await
                 {
                     sent_ids.lock().await.insert(resp.event_id);
-    let result = provider
-        .chat_stream(
-            &prompt,
-            &ctx.project_root.to_string_lossy(),
-            resume_session_id.as_deref(),
-            &mut cancel_rx,
-            move |token| {
-                let mut buf = buffer_for_callback.lock().unwrap();
-                buf.push_str(token);
-                // Flush complete paragraphs as they arrive.
-                let paragraphs = drain_complete_paragraphs(&mut buf);
-                for chunk in paragraphs {
-                    sent_any_chunk_for_callback.store(true, Ordering::Relaxed);
-                    let _ = msg_tx_for_callback.send(chunk);
                 }
 
                 // Store the MCP oneshot sender so the event handler can