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>

agent/test/loopbackLiteral.test.ts

@@ -0,0 +1,39 @@
+import { describe, expect, it } from 'vitest'
+import { isLoopbackHostLiteral } from '../src/net/loopbackLiteral.js'
+
+describe('isLoopbackHostLiteral — strict loopback-literal check (FIX C-host-1 / anti-SSRF)', () => {
+  it('accepts exact loopback literals', () => {
+    expect(isLoopbackHostLiteral('localhost')).toBe(true)
+    expect(isLoopbackHostLiteral('::1')).toBe(true)
+    expect(isLoopbackHostLiteral('[::1]')).toBe(true)
+  })
+
+  it('accepts any well-formed IPv4 in 127.0.0.0/8', () => {
+    expect(isLoopbackHostLiteral('127.0.0.1')).toBe(true)
+    expect(isLoopbackHostLiteral('127.0.0.2')).toBe(true)
+    expect(isLoopbackHostLiteral('127.5.5.5')).toBe(true)
+    expect(isLoopbackHostLiteral('127.255.255.255')).toBe(true)
+  })
+
+  it('rejects non-loopback IPs and wildcards', () => {
+    expect(isLoopbackHostLiteral('0.0.0.0')).toBe(false)
+    expect(isLoopbackHostLiteral('192.168.1.10')).toBe(false)
+    expect(isLoopbackHostLiteral('10.0.0.5')).toBe(false)
+    expect(isLoopbackHostLiteral('::')).toBe(false)
+  })
+
+  it('REJECTS suffixed hostnames that merely start with 127. (the S-GATE bypass)', () => {
+    expect(isLoopbackHostLiteral('127.0.0.1.attacker.example.com')).toBe(false)
+    expect(isLoopbackHostLiteral('127.evil.net')).toBe(false)
+    expect(isLoopbackHostLiteral('127.0.0.1.evil.example.com')).toBe(false)
+    expect(isLoopbackHostLiteral('127.0.0.1x')).toBe(false)
+  })
+
+  it('rejects malformed / non-dotted-quad partials and out-of-range octets', () => {
+    expect(isLoopbackHostLiteral('127.1')).toBe(false)
+    expect(isLoopbackHostLiteral('127.0.0.256')).toBe(false)
+    expect(isLoopbackHostLiteral('0127.0.0.1')).toBe(false)
+    expect(isLoopbackHostLiteral('')).toBe(false)
+    expect(isLoopbackHostLiteral('127')).toBe(false)
+  })
+})