v0.42.0 — Halo LED dashboard card

Added

• Halo LED card on the dashboard — a Standby toggle (dim-when-idle) and a Brightness slider (0–100 %), for parity with the ESP web UI and the integration. Optimistic writes with retry/backoff; auto-hidden if the charger has no halo ring.

Fixed

• fetchJSON now forwards POST options (writes previously fell back to a GET). Halo read hardened with retry/backoff.

Verified end-to-end against a real Pulsar MAX.