v1.18.0 — One-click firmware updates, fleet block odds, stability fixes

One-click AxeOS firmware updates (Pro bulk / free single, fail-closed Bitaxe-only), per-coin fleet block odds, NerdQAxe monitoring, and stability fixes (chain-stats + block-found alert moved off the poll lock). Recommended update for everyone.

Full notes: https://bitaxeballer.com/changelog.html