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.

term-relay/test/integration/data-plane.test.ts

@@ -0,0 +1,101 @@
+import { describe, test, expect } from 'vitest'
+import { createMuxSession, type MuxSession } from '../../mux/mux-session.js'
+import { createRelayNode } from '../../data-plane/relay-node.js'
+import { loadDataPlaneConfig } from '../../data-plane/config.js'
+import type { AgentListener, AgentTunnel } from '../../data-plane/agent-listener.js'
+import type { UpgradeDecision, UpgradeRequest } from '../../data-plane/upgrade.js'
+
+const config = loadDataPlaneConfig({
+  BASE_DOMAIN: 'term.example.com',
+  TLS_CERT_PATH: '/c',
+  TLS_KEY_PATH: '/k',
+  AGENT_CA_CERT_PATH: '/ca',
+  RELAY_NODE_ID: 'node-1',
+})
+
+const noSchedule = () => ({ cancel: () => {} })
+
+/** Build a real relay↔agent MuxSession pair; the agent echoes each DATA payload back verbatim. */
+function wiredTunnel(hostId: string): AgentTunnel {
+  let agent!: MuxSession
+  const relay = createMuxSession({
+    role: 'relay',
+    sendWire: (f) => agent.onWire(f),
+    onOpen: () => {},
+    onData: () => {},
+    onClose: () => {},
+    onDead: () => {},
+    maxFrameBytes: 1024,
+    initialWindowBytes: 1_000_000,
+    schedule: noSchedule,
+  })
+  agent = createMuxSession({
+    role: 'agent',
+    sendWire: (f) => relay.onWire(f),
+    onOpen: (_open, stream) => {
+      // The agent dials its local ws://127.0.0.1:3000 (here: an echo) — OPAQUE bytes only.
+      stream.onData((bytes) => stream.writeData(bytes))
+    },
+    onData: () => {},
+    onClose: () => {},
+    onDead: () => {},
+    maxFrameBytes: 1024,
+    initialWindowBytes: 1_000_000,
+    schedule: noSchedule,
+  })
+  return { hostId, accountId: 'acct-1', session: relay, closeTunnel: () => relay.close() }
+}
+
+function listenerWith(tunnels: Map<string, AgentTunnel>): AgentListener {
+  return { attach: () => {}, tunnels: () => tunnels, close: () => {} }
+}
+
+function browserWs() {
+  let onMsg: ((b: Uint8Array) => void) | null = null
+  return {
+    sent: [] as Uint8Array[],
+    closedWith: undefined as number | undefined,
+    send(b: Uint8Array) {
+      this.sent.push(b)
+    },
+    close(code?: number) {
+      this.closedWith = code
+    },
+    onMessage(h: (b: Uint8Array) => void) {
+      onMsg = h
+    },
+    onClose() {},
+    type: (b: Uint8Array) => onMsg?.(b),
+  }
+}
+
+function okDecision(hostId: string): UpgradeDecision {
+  return {
+    ok: true,
+    hostId,
+    acceptedSubprotocol: 'term.relay.v1',
+    open: { streamId: 0, subdomain: 'alice', requestPath: '/', originHeader: 'o', remoteAddrHash: 'h', capabilityTokenRef: 'jti' },
+  }
+}
+
+describe('data-plane integration (T13) — end-to-end opaque splice through a real MuxSession pair', () => {
+  test('INV2: bytes round-trip browser → agent → browser byte-identical, never parsed', async () => {
+    const tunnels = new Map([['host-A', wiredTunnel('host-A')]])
+    const node = createRelayNode({ config, listener: listenerWith(tunnels), authorize: async () => okDecision('host-A') })
+    const ws = browserWs()
+    await node.handleBrowserUpgrade({} as UpgradeRequest, ws)
+    const payload = new TextEncoder().encode('echo-me-🔒-ciphertext')
+    ws.type(payload)
+    expect(ws.sent).toHaveLength(1)
+    expect([...ws.sent[0]!]).toEqual([...payload]) // opaque round-trip
+  })
+
+  test('INV1: an upgrade authorized for a host not on this node cannot reach any tunnel', async () => {
+    const tunnels = new Map([['host-A', wiredTunnel('host-A')]])
+    const node = createRelayNode({ config, listener: listenerWith(tunnels), authorize: async () => okDecision('host-B') })
+    const ws = browserWs()
+    await node.handleBrowserUpgrade({} as UpgradeRequest, ws)
+    expect(ws.closedWith).toBe(1013) // no tunnel for host-B; A is never reachable by another host's token
+    expect(ws.sent).toHaveLength(0)
+  })
+})