Middleware safety net skips recovery when commit_and_open_pr tool fails

Description

In `open_pr.py:87`, the middleware checks `'success' in payload` rather than `payload['success'] == True`. The string `'success'` is always in the payload dict as a key — even when its value is `False`. The recovery logic is never triggered on tool failure.

Reproduction

payload = {'success': False, 'error': 'PR creation failed'}
if 'success' in payload:  # True — key exists, value ignored
    pass  # Recovery skipped