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/config.test.ts

@@ -0,0 +1,57 @@
+import { describe, test, expect } from 'vitest'
+import { loadDataPlaneConfig } from '../data-plane/config.js'
+
+const base = {
+  BASE_DOMAIN: 'term.example.com',
+  TLS_CERT_PATH: '/etc/relay/cert.pem',
+  TLS_KEY_PATH: '/etc/relay/key.pem',
+  AGENT_CA_CERT_PATH: '/etc/relay/ca.pem',
+  RELAY_NODE_ID: 'node-1',
+} satisfies NodeJS.ProcessEnv
+
+describe('loadDataPlaneConfig (T1, INV9 fail-fast)', () => {
+  test('happy path returns a frozen typed config with defaults applied', () => {
+    const cfg = loadDataPlaneConfig(base)
+    expect(cfg.baseDomain).toBe('term.example.com')
+    expect(cfg.bindHost).toBe('0.0.0.0')
+    expect(cfg.maxFrameBytes).toBe(1024 * 1024)
+    expect(cfg.initialWindowBytes).toBe(256 * 1024)
+    expect(cfg.heartbeatIntervalMs).toBe(15_000)
+    expect(cfg.routeTtlMs).toBe(45_000)
+    // agentCaChainPath falls back to agentCaCertPath when unset.
+    expect(cfg.agentCaChainPath).toBe('/etc/relay/ca.pem')
+    expect(Object.isFrozen(cfg)).toBe(true)
+  })
+
+  test('throws when BASE_DOMAIN is missing', () => {
+    expect(() => loadDataPlaneConfig({ ...base, BASE_DOMAIN: undefined })).toThrow(/baseDomain/)
+  })
+
+  test('throws when TLS_CERT_PATH / TLS_KEY_PATH missing (fail-fast)', () => {
+    expect(() => loadDataPlaneConfig({ ...base, TLS_CERT_PATH: undefined })).toThrow(/tlsCertPath/)
+    expect(() => loadDataPlaneConfig({ ...base, TLS_KEY_PATH: undefined })).toThrow(/tlsKeyPath/)
+  })
+
+  test('throws when AGENT_CA_CERT_PATH (mTLS trust-anchor) missing — Finding-4 footgun', () => {
+    expect(() => loadDataPlaneConfig({ ...base, AGENT_CA_CERT_PATH: undefined })).toThrow(
+      /agentCaCertPath/,
+    )
+  })
+
+  test('throws on non-numeric MAX_FRAME_BYTES', () => {
+    expect(() => loadDataPlaneConfig({ ...base, MAX_FRAME_BYTES: 'not-a-number' })).toThrow(
+      /maxFrameBytes/,
+    )
+  })
+
+  test('error message never echoes secret values (INV9)', () => {
+    try {
+      loadDataPlaneConfig({ ...base, TLS_KEY_PATH: undefined, MAX_FRAME_BYTES: 'xyz' })
+      throw new Error('should have thrown')
+    } catch (e) {
+      const msg = (e as Error).message
+      expect(msg).not.toContain('/etc/relay/key.pem')
+      expect(msg).not.toContain('xyz')
+    }
+  })
+})