feat(tunnel): zero-touch tunnel enrollment — control-plane PKI, host agent, iOS, nginx isolation

Customers install one command / log in once; hardware-generated keys never leave the
device; CSRs return certs + subdomain; frpc + base-app run as durable services. No .p12,
no manual cert import. Implements the MVP fast-path of docs/PLAN_TUNNEL_AUTOMATION.md.

Control-plane / PKI (control-plane/):
- ca/x509-assembler.ts: single KMS-signed real X.509 issuance primitive (Ed25519 + P-256)
- ca/csr-ec.ts: P-256 PKCS#10 proof-of-possession (verifyCsrPoPEc) + CSR-key routing
- ca/frpclient-issue.ts, ca/device-issue.ts: P-256 frp-client + device leaf signers
- ca/rotate.ts + api/renew.ts: real-X.509 /renew + /device/:id/renew (mTLS current cert)
- registry/devices.ts: device registry + per-account cap/rate-limit
- auth/session.ts: device:enroll capability token mint/verify
- api/device-enroll.ts: POST /device/enroll (ownership-gated, deny-by-default)
- pairing/native-redeem.ts + shared gateAndConsumePairingCode; api/provision.ts native arm
- boot/native-ca.ts + main.ts: wire two P-256 CAs + issuers + routers (dev / KMS fail-fast)

Contracts: relay-contracts enroll right; relay-auth SPIFFE /device/ arm + spiffeIdFor(kind)

Host agent (agent/):
- transport/frpcToml.ts; provision/frpcBinary.ts + untar.ts (verify-download + traversal-safe extract)
- keys P-256 keygen/CSR/loadIdentity; service two-unit install + BIND_HOST loopback S-GATE
- net/loopbackLiteral.ts strict guard; health/probe.ts + transport/frpSupervise.ts; cli pair --install

iOS (ios/Packages/ClientTLS): SecureEnclaveKey + CertificateSigningRequest + DeviceEnrollmentClient
+ Keychain enroll refactor (SecKey/Security.framework end-to-end, avoids the -25300 trap)

Isolation (deploy/nginx): njs/getCertSub.js SAN parser + zone-anchored map -> 403

Verified: 758 tests green (control-plane 246, agent 267, relay-auth 133, relay-contracts 85,
iOS ClientTLS 27), all tsc clean; real nginx+njs docker 403/200/400; Swift CSR accepted by
the real control-plane verifier; frpc extract byte-identical to `tar -xO`. Cross-validation
caught + fixed 5 real defects (1 critical, 4 high). Remaining = infra (KMS, nginx deploy,
VPS frps, physical iPhone) per PROGRESS_LOG runbook.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

deploy/nginx/test/integration/nginx.test.conf

@@ -0,0 +1,39 @@
+# A3 integration nginx.conf — exercises the REAL binding stack end-to-end: getCertSub.js (njs),
+# js_set $cert_sub, the $cert_host_ok map, and the single `if → return 403`.
+#
+# ONLY delta from the production deploy/nginx/frp-mtls.conf: the location returns a stub `200 ok`
+# instead of proxying to the frps vhost (no frps needed to prove the AUTH gate), and the listener is
+# a plain :8470 (not 127.0.0.1) so the published container port is reachable. The binding logic —
+# ssl_verify_client + njs SAN parse + map + if→403 — is byte-identical to prod.
+
+load_module modules/ngx_http_js_module.so;   # VPS prereq (main context)
+
+events {}
+
+http {
+    js_import certsub from njs/getCertSub.js;              # mounted at /etc/nginx/njs/getCertSub.js
+    js_set    $cert_sub certsub.getCertSub;
+
+    map "$cert_sub:$ssl_server_name" $cert_host_ok {
+        "~^(?<s>[^:]+):(?P=s)\."  1;
+        default                   0;
+    }
+
+    server {
+        listen 8470 ssl;
+        server_name ~^.+\.terminal\.yaojia\.wang$;
+
+        ssl_certificate     /certs/server.crt;
+        ssl_certificate_key /certs/server.key;
+
+        # data-path gate: only device-CA-signed client certs get past the handshake
+        ssl_verify_client on;
+        ssl_client_certificate /certs/ca.crt;
+        ssl_verify_depth 1;
+
+        # A3 cert→Host binding — the one `if` guarding the single return; rule lives in the map.
+        if ($cert_host_ok = 0) { return 403; }
+
+        location / { return 200 "ok\n"; }   # PROD: proxy_pass http://127.0.0.1:7080; (frps vhost)
+    }
+}