feat: self-host fonts, styled block page, wildcard TLS (#16)

* perf: optimize hot path — RwLock, inline filtering, pre-allocated strings

- Mutex → RwLock for cache, blocklist, and overrides (concurrent read access)
- Make cache.lookup() and overrides.lookup() take &self (read-only)
- Eliminate 3 Vec allocations per DnsPacket::write() via inline filtering
- Pre-allocate domain strings with capacity 64 in parse path
- Add criterion micro-benchmarks (hot_path + throughput)
- Add bench README documenting both benchmark suites

Measured improvement: ~14% faster parsing, ~9% pipeline throughput,
round-trip cached 733ns → 698ns (~2.3M queries/sec).

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

* chore: simplify benchmark code after review

- Remove redundant DnsHeader::new() (already set by DnsPacket::new())
- Remove unused DnsHeader import
- Change simulate_cached_pipeline to take &DnsCache (lookup is &self now)
- Remove unnecessary mut on cache in cache_lookup_miss bench

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

* site: landing page overhaul, blog, benchmarks, numa.rs domain

Landing page:
- Split features into 3-layer card layout (Block & Protect, Developer Tools, Self-Sovereign DNS)
- Add DoH and conditional forwarding to comparison table
- Fix performance claim (2.3M → 2.0M qps to match benchmarks)
- Add all 3 install methods (brew, cargo, curl)
- Add OG tags + canonical URL for numa.rs
- Fix code block whitespace rendering
- Update roadmap with .onion bridge phase

Blog:
- Add "Building a DNS Resolver from Scratch in Rust" post
- Blog index + template for future posts

Other:
- CNAME for GitHub Pages (numa.rs)
- Benchmark results (bench/results.json)

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

* feat: self-host fonts, styled block page, wildcard TLS

Fonts:
- Replace Google Fonts CDN with self-hosted woff2 (73KB, 5 files)
- Serve fonts from API server via include_bytes! (dashboard works offline)
- Proxy error pages use system fonts (zero external deps when DNS is broken)
- Fix Instrument Serif font-weight: use 400 (only available weight) instead of synthetic bold 600/700

Proxy:
- Styled "Blocked by Numa" page when blocked domain hits the proxy (was confusing "not a .numa domain" error)
- Extract shared error_page() template for 403 + 404 pages (deduplicate ~160 lines of CSS)

TLS:
- Add wildcard SAN *.numa to cert — unregistered .numa domains get valid HTTPS (styled 404 without cert warning)

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

---------

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

site/dashboard.html

@@ -4,9 +4,7 @@
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <title>Numa — Dashboard</title>
-<link rel="preconnect" href="https://fonts.googleapis.com">
-<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
-<link href="https://fonts.googleapis.com/css2?family=Instrument+Serif:ital@0;1&family=DM+Sans:opsz,wght@9..40,400;9..40,500;9..40,600&family=JetBrains+Mono:wght@400;500&display=swap" rel="stylesheet">
+<link rel="stylesheet" href="/fonts/fonts.css">
 <style>
 *, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }