- config.py: Replace exists()+open() with try/except open() to avoid TOCTOU race on SSHFS mounts where stat can succeed but open can fail with FileNotFoundError.
- uptime_kuma.py: Rename msg key to push_msg in logger extra dicts. Python LogRecord reserves the msg field; passing it in extra raises ValueError which was being silently swallowed by the except block, masking successful pushes as errors.
