No. They represent donuts.
Glazed donuts to be exact.
They were stolen from the god Helios.
Perhaps. The light of God within them.
No, their origin is from the worship of pagan solar deities (Helios/Horus/Ra/Apsu/Balder/Apollo/etc.) and represent the Sun.
Halos do suggest an active crown chakra, but aren’t expressions of it – they are a byproduct of awakened kundalini, which in Christian terms translate as either the Holy Spirit or the Holy Fire. Gold halos are masculine and silver are feminine. Crown chakra expressions may also include flecks of these colours, but are predominantly purple.