- YouTube: warn when only Node.js is installed but yt-dlp config file
is missing (previously returned "ok" incorrectly)
- Douyin: use `mcporter list` instead of calling with a hardcoded
invalid share URL that always fails
- cli: replace bare `except:` with `except Exception:` in
`_detect_environment` to avoid catching KeyboardInterrupt/SystemExit
- cli: fix unclosed file handle for cloud VM detection
- config: use `os.open()` with 0o600 mode to eliminate permission
race window when saving credentials
Shawn