Tailscale's stub resolver (100.100.100.100) intermittently times out
or SERVFAILs under bursty concurrent lookups (a known upstream issue,
e.g. tailscale/tailscale#6850, #10768, #8829), which was breaking HACS
updates in the Home Assistant container (network_mode: host, so it
inherits nixserve's own resolv.conf). Point nixserve at the local
Pi-hole instead and disable Tailscale's accept-dns so it can't
override it.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>