feat(transport,tunnel): implement Wave 3 — QUIC transport + split-tunnel router

aura-transport: quinn 0.11 endpoint with HTTP/3 mimicry (ALPN h3/h3-29,
Chrome-like transport params), outer-TLS accept-any (real auth is the inner
Aura handshake), packet padding to HTTPS sizes; AuraServer/AuraClient drive the
proto handshake over a QUIC bidi stream; AuraConnection impls
aura_proto::PacketConnection (full-duplex via Session::split + per-half mutex).
14 tests incl. a real-QUIC loopback end-to-end (crypto+pki+proto+transport).

aura-tunnel: RouteTable (longest-prefix split-tunnel classify), AuraDns
(hickory) host-route registration, AuraRouter over a PacketIo TUN seam +
Arc<dyn PacketConnection>, AuraTun (tun 0.8 unix; wintun cfg-gated Windows).
10 tests (route classify/priority, dst-IP parse, mock router). send_direct is a
v1 stub. Whole workspace: tests green, clippy clean.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Cargo.lock

@@ -267,11 +267,13 @@ dependencies = [
  "anyhow",
  "async-trait",
  "aura-crypto",
+ "aura-pki",
  "aura-proto",
  "bytes",
  "quinn",
  "rand 0.8.6",
  "rustls",
+ "rustls-pemfile",
  "rustls-pki-types",
  "thiserror 1.0.69",
  "tokio",
@@ -2205,6 +2207,15 @@ dependencies = [
  "security-framework",
 ]
 
+[[package]]
+name = "rustls-pemfile"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dce314e5fee3f39953d46bb63bb8a46d40c2f8fb7cc5a3b6cab2bde9721d6e50"
+dependencies = [
+ "rustls-pki-types",
+]
+
 [[package]]
 name = "rustls-pki-types"
 version = "1.14.1"