Fix WebCRT connect crash from invalid Netmiko session_log wrapper.

Use a BytesIO subclass for live connect echo so Netmiko accepts the log object again.

Co-authored-by: Cursor <cursoragent@cursor.com>

netx_api/webcrt_session_registry.py

@@ -19,6 +19,7 @@ from .ne_session_factory import (
     get_cli_hop_guard,
     open_netmiko_connection,
 )
+from .ne_session_connect import _ProgressBytesIO
 from .webcrt_channel import (
     _audit,
     _capture_raw_channel,
@@ -222,11 +223,12 @@ def _finish_connect(
     connect_timeout: int,
     client: str,
 ) -> None:
-    log_buf = io.BytesIO()
-
     def _progress(text: str) -> None:
         sess.push_connect_echo(text)
 
+    # Must be BufferedIOBase subclass — Netmiko rejects custom log wrappers.
+    log_buf = _ProgressBytesIO(_progress)
+
     try:
         conn = open_netmiko_connection(
             creds,