feat(relay): rendezvous-relay service — 7 packages + plans (contracts/transport/agent/control-plane/e2e/auth/web)

Multi-tenant reverse-tunnel service ("ngrok for Claude Code" with E2E): a
host-agent dials OUT to an operator-run relay; external devices reach the host
THROUGH the relay, routed by per-tenant subdomain, forwarding ciphertext only
(the relay never sees plaintext). Lets a customer reach their own self-hosted
web-terminal from anywhere with zero networking setup.

Packages — all tsc-strict + vitest green (656 tests), cross-package integration verified:
- relay-contracts: frozen shared contracts (mux frame codec, data model,
  capability token, E2E envelope, pairing) — the src/types.ts analog
- term-relay:   native WS mux + stateless data plane (subdomain routing, ciphertext forward)
- agent:        host-agent (pairing, per-host Ed25519 + mTLS dial-out, forwards to 127.0.0.1:3000)
- control-plane: accounts/hosts registry, pairing-code flow, routing table, provisioning
- relay-e2e:    browser<->agent E2E (X25519 ECDH through relay, AEAD, anti-replay, recoverable replay key)
- relay-auth:   Passkey/WebAuthn, capability tokens, per-host certs, deny-by-default tenant isolation
- relay-web:    browser login + Web Crypto E2E + client-side preview rendering

Security invariants INV1-15 enforced; cross-tenant isolation CI tripwire live
(.github/workflows/relay-tripwire.yml). Design + implementation-level plans in
docs/PLAN_RELAY_*.md and docs/EXPLORE_RELAY_SERVICE.md.

NOTE: generated autonomously per the reviewed plans. The security-critical
packages (relay-e2e, relay-auth) REQUIRE expert security audit before any real
deployment — passing tests prove self-consistency, not resistance to attackers.
Base app (src/, public/) unchanged; concurrent desktop work left uncommitted.

control-plane/test/ca.test.ts

@@ -0,0 +1,73 @@
+import { describe, test, expect, vi } from 'vitest'
+import { createMemoryStores } from '../src/store/memory.js'
+import { createHostRegistry } from '../src/registry/hosts.js'
+import { createLeafSigner, LeafSignError } from '../src/ca/sign.js'
+import { inProcessCaSigner } from '../src/boot/ca-wiring.js'
+import { buildCsr, verifyCsrPoP } from '../src/ca/csr.js'
+import { fingerprint } from '../src/ca/fingerprint.js'
+import { generateEd25519, sealToX25519, openFromX25519, generateX25519 } from '../src/util/crypto.js'
+import { randomBytes } from 'node:crypto'
+
+function boundHost() {
+  const stores = createMemoryStores()
+  const hosts = createHostRegistry({ hosts: stores.hosts })
+  return { stores, hosts }
+}
+
+describe('T8 signHostLeaf — INV14 registry-gated + CSR PoP', () => {
+  test('active registered host + valid CSR → cert signed under CA', async () => {
+    const { stores, hosts } = boundHost()
+    const { publicKeyRaw, privateKey } = generateEd25519()
+    const host = await hosts.bindHost({ accountId: '11111111-1111-4111-8111-111111111111', subdomain: 'alice', agentPubkey: publicKeyRaw, enrollFpr: fingerprint(publicKeyRaw) })
+    const signer = createLeafSigner({ hosts: stores.hosts, signer: inProcessCaSigner(), caChainDer: [] })
+    const { cert } = await signer.signHostLeaf(host.hostId, publicKeyRaw, buildCsr(privateKey, publicKeyRaw))
+    expect(cert.length).toBeGreaterThan(0)
+  })
+
+  test('CSR proof-of-possession fails even for a registered active key → reject, KMS never called', async () => {
+    const { stores, hosts } = boundHost()
+    const { publicKeyRaw } = generateEd25519()
+    const host = await hosts.bindHost({ accountId: '11111111-1111-4111-8111-111111111111', subdomain: 'alice', agentPubkey: publicKeyRaw, enrollFpr: fingerprint(publicKeyRaw) })
+    const spy = inProcessCaSigner()
+    const signSpy = vi.spyOn(spy, 'sign')
+    const signer = createLeafSigner({ hosts: stores.hosts, signer: spy, caChainDer: [] })
+    // forge a CSR: correct embedded pub but a garbage signature
+    const forged = new Uint8Array(96)
+    forged.set(publicKeyRaw, 0)
+    forged.set(randomBytes(64), 32)
+    expect(verifyCsrPoP(forged).ok).toBe(false)
+    await expect(signer.signHostLeaf(host.hostId, publicKeyRaw, forged)).rejects.toBeInstanceOf(LeafSignError)
+    expect(signSpy).not.toHaveBeenCalled()
+  })
+
+  test('INV14 gate: unregistered pubkey → throws, KMS sign never invoked', async () => {
+    const { stores } = boundHost()
+    const { publicKeyRaw, privateKey } = generateEd25519()
+    const spy = inProcessCaSigner()
+    const signSpy = vi.spyOn(spy, 'sign')
+    const signer = createLeafSigner({ hosts: stores.hosts, signer: spy, caChainDer: [] })
+    await expect(signer.signHostLeaf('00000000-0000-4000-8000-000000000000', publicKeyRaw, buildCsr(privateKey, publicKeyRaw))).rejects.toBeInstanceOf(LeafSignError)
+    expect(signSpy).not.toHaveBeenCalled()
+  })
+
+  test('revoked host cannot be signed (INV12+INV14)', async () => {
+    const { stores, hosts } = boundHost()
+    const { publicKeyRaw, privateKey } = generateEd25519()
+    const host = await hosts.bindHost({ accountId: '11111111-1111-4111-8111-111111111111', subdomain: 'alice', agentPubkey: publicKeyRaw, enrollFpr: fingerprint(publicKeyRaw) })
+    await hosts.setHostStatus(host.hostId, 'revoked')
+    const signer = createLeafSigner({ hosts: stores.hosts, signer: inProcessCaSigner(), caChainDer: [] })
+    await expect(signer.signHostLeaf(host.hostId, publicKeyRaw, buildCsr(privateKey, publicKeyRaw))).rejects.toBeInstanceOf(LeafSignError)
+  })
+})
+
+describe('host content-secret wrap (FIX 3 security property)', () => {
+  test('only the matching private key can unwrap; raw secret absent from blob', () => {
+    const recipient = generateX25519()
+    const secret = new Uint8Array(randomBytes(32))
+    const blob = sealToX25519(recipient.publicKeyRaw, secret)
+    expect(Buffer.from(blob).includes(Buffer.from(secret))).toBe(false) // raw secret not in ciphertext
+    expect(Buffer.from(openFromX25519(recipient.privateKey, blob)).equals(Buffer.from(secret))).toBe(true)
+    const wrong = generateX25519()
+    expect(() => openFromX25519(wrong.privateKey, blob)).toThrow()
+  })
+})