- Replace async create_bind_task/poll_bind_result with synchronous
httpx.Client equivalents, eliminating manual event loop management
- Move _render_qr and full qr_register() entry-point into onboard.py,
mirroring the Feishu onboarding pattern
- Remove _qqbot_render_qr and _qqbot_qr_flow from gateway.py (~90 lines);
call site becomes a single qr_register() import
- Fix potential segfault: previous code called loop.close() in the EXPIRED
branch and again in the finally block (double-close crashed under uvloop)