fix: update /help test to expect botCommand dispatch, fix PTY fd leak in claude_code.rs (#451, #452)

The /help test expected the help overlay to appear, but /help now goes
through botCommand like other slash commands. Updated the test to match.

Also added reader thread join and child.wait() calls to
claude_code.rs to prevent PTY master fd leaks from web UI chat sessions.

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

server/src/llm/providers/claude_code.rs

@@ -256,7 +256,7 @@ fn run_pty_session(
     // Read NDJSON lines from stdout
     let (line_tx, line_rx) = std::sync::mpsc::channel::<Option<String>>();
 
-    std::thread::spawn(move || {
+    let reader_handle = std::thread::spawn(move || {
         let buf_reader = BufReader::new(reader);
         slog!("[pty-debug] Reader thread started");
         for line in buf_reader.lines() {
@@ -284,6 +284,8 @@ fn run_pty_session(
     loop {
         if cancelled.load(Ordering::Relaxed) {
             let _ = child.kill();
+            let _ = child.wait();
+            let _ = reader_handle.join();
             return Err("Cancelled".to_string());
         }
 
@@ -365,8 +367,11 @@ fn run_pty_session(
             }
             // If still running after 2s, kill it
             let _ = child.kill();
+            let _ = child.wait();
         }
     }
+    // Wait for the reader thread to release the cloned PTY master fd.
+    let _ = reader_handle.join();
     Ok(())
 }