feat: DoH server endpoint + DoT enabled by default (#79)

* chore: document multi-forwarder and cache warming in config and README

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: DNS-over-HTTPS server endpoint (RFC 8484)

Serve DoH at POST /dns-query on the existing HTTPS proxy (port 443).
Automatically enabled when proxy TLS is active — no config needed.
Also fix zone map priority so local zones override RFC 6762 .local
special-use handling.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* style: cargo fmt

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: remove GoatCounter analytics from site

GoatCounter domains (goatcounter.com, gc.zgo.at) are blocked by
Hagezi Pro, which is Numa's default blocklist. A DNS privacy tool
should not embed analytics that its own resolver blocks.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: enable DoT listener by default

DoT now starts automatically with `sudo numa`, matching the proxy and
DoH which are already on by default. The self-signed CA infrastructure
is shared with the proxy, so there is no additional setup. This makes
`numa setup-phone` work out of the box.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

README.md

@@ -139,6 +139,8 @@ From Machine B: `curl http://api.numa` → proxied to Machine A's port 8000. Ena
 - [x] DNS-over-TLS listener — encrypted client connections (RFC 7858, ALPN strict)
 - [x] Recursive resolution + DNSSEC — chain-of-trust, NSEC/NSEC3
 - [x] SRTT-based nameserver selection
+- [x] Multi-forwarder failover — multiple upstreams with SRTT ranking, fallback pool
+- [x] Cache warming — proactive resolution for configured domains
 - [x] Mobile onboarding — `setup-phone` QR flow, mobile API, mobileconfig profiles
 - [ ] pkarr integration — self-sovereign DNS via Mainline DHT
 - [ ] Global `.numa` names — DHT-backed, no registrar