Remove the DNS over HTTPS (DoH) proxy feature built on CoreDNS due to
security vulnerabilities (GO-2025-3942, GO-2026-4289).
This removes:
- Standalone proxy-dns command (cloudflared proxy-dns)
- Tunnel subcommand (cloudflared tunnel proxy-dns)
- Proxy-dns flags for tunnel run (--proxy-dns, --proxy-dns-port, etc.)
- Config file resolver section support
- tunneldns/ package (CoreDNS-based implementation)
- Related component tests
BREAKING CHANGE: The proxy-dns feature is no longer available.
Users should migrate to alternative DNS over HTTPS solutions.
In addition to supporting sampling support for streaming logs,
cloudflared tail also supports this via `--sample 0.5` to sample 50%
of your log events.
To help accommodate web browser interactions with websockets, when a
streaming logs session is requested for the same actor while already
serving a session for that user in a separate request, the original
request will be closed and the new request start streaming logs
instead. This should help with rogue sessions holding on for too long
with no client on the other side (before idle timeout or connection
close).