If I change the config yaml of an ESPHome device (e.g. to add a new binary sensor) and update it, do I then need to restart the HA server in order for the new config/sensor to be detected?
No, you don’t need to restart HA, but browser sometimes doesn’t show this new sensor unless you hit ctrl+F5 to refresh page.
But, what i do when i remove any sensor from esphome is remove and re-add device in HA - to delete removed sensors from HA, otherwise they stay in Ha as ‘unavailable’