Add a CanIndicatorLight capability and status-aware Indicator toggle button. The indicator LED on the ASH21-B, ADC2W and ASH42-B is controlled via the LightGlobal config (configManager get/setConfig); add indicatorLightOn/Off/Status to Dahua_RPC and a model-specific 'Amcrest ASH42-B RPC' Controls row, with the capability also enabled on the ASH21-B/ADC2W/generic rows. Migration zm_update-1.39.13.sql adds the column.
Add Dahua_RPC keepAlive (global.keepAlive) wired into a 30s zmcontrol idle tick, plus session-expiry re-login retry in set_config and the status queries, so the long-running control daemon does not silently fail after the ~60s session timeout.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>