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>

relay-auth/test/mtls.test.ts

@@ -26,7 +26,7 @@ describe('SPIFFE-ID scheme (T9)', () => {
   it('formats and round-trips account/host', () => {
     const id = spiffeIdFor('acct-A', 'host-1', DOMAIN)
     expect(id).toBe('spiffe://relay.example.com/account/acct-A/host/host-1')
-    expect(parseSpiffeId(id)).toEqual({ accountId: 'acct-A', hostId: 'host-1' })
+    expect(parseSpiffeId(id)).toEqual({ accountId: 'acct-A', id: 'host-1', kind: 'host' })
   })
 
   it('rejects a path-traversal / wildcard SPIFFE-ID', () => {
@@ -73,6 +73,15 @@ describe('agent cert verification (INV4/INV14)', () => {
     const r = await verifyAgentCert('leaf', 'ca', NOW, hosts, certParser(cert))
     expect(r).toMatchObject({ ok: false, reason: 'chain_invalid' })
   })
+
+  it('refuses a device-kind cert on the host channel even if the id collides with an enrolled host (kind guard)', async () => {
+    // Trust-broadening guard: a /device/ SAN whose id happens to equal an enrolled hostId
+    // (same account) must NOT be accepted by the host-agent verifier. The host channel is
+    // host-only; device certs are enforced at nginx :8470, not here.
+    const cert = { ...validCert, spiffeUri: spiffeIdFor('acct-A', 'host-1', DOMAIN, 'device') }
+    const r = await verifyAgentCert('leaf', 'ca', NOW, hosts, certParser(cert))
+    expect(r).toMatchObject({ ok: false, reason: 'not_host_cert' })
+  })
 })
 
 describe('defaultParseX509 real X.509 path validation (INV4/INV14)', () => {