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/inv-tripwires.test.ts

@@ -0,0 +1,65 @@
+import { describe, test, expect } from 'vitest'
+import { readdirSync, readFileSync, statSync } from 'node:fs'
+import { fileURLToPath } from 'node:url'
+import { createMuxSession, type MuxSession } from '../mux/mux-session.js'
+import type { MuxOpen } from '../mux/frame-codec.js'
+
+/** Recursively collect .ts source files under a directory. */
+function tsFiles(dir: string): string[] {
+  const out: string[] = []
+  for (const entry of readdirSync(dir)) {
+    const full = `${dir}/${entry}`
+    if (statSync(full).isDirectory()) out.push(...tsFiles(full))
+    else if (entry.endsWith('.ts')) out.push(full)
+  }
+  return out
+}
+
+const MUX_DIR = fileURLToPath(new URL('../mux', import.meta.url))
+const DP_DIR = fileURLToPath(new URL('../data-plane', import.meta.url))
+const TERMINAL_PARSER_RE = /xterm|ansi|vt100|terminal-parser/i
+
+describe('P1 invariant tripwires (T13)', () => {
+  test('INV11: no mux/ or data-plane/ source imports a terminal/ANSI parser', () => {
+    const files = [...tsFiles(MUX_DIR), ...tsFiles(DP_DIR)]
+    expect(files.length).toBeGreaterThan(0)
+    const offenders = files.filter((f) => {
+      const src = readFileSync(f, 'utf8')
+      const importLines = src.split('\n').filter((l) => /\bimport\b/.test(l) || /\bfrom\b/.test(l))
+      return importLines.some((l) => TERMINAL_PARSER_RE.test(l))
+    })
+    expect(offenders).toEqual([])
+  })
+
+  test('INV2: a plaintext marker rides DATA as OPAQUE bytes; never inspected or retained', () => {
+    const marker = new TextEncoder().encode('SECRET-PLAINTEXT-MARKER')
+    let delivered: Uint8Array | null = null
+    let agent!: MuxSession
+    const relay = createMuxSession({
+      role: 'relay',
+      sendWire: (f) => agent.onWire(f),
+      onOpen: () => {},
+      onData: () => {},
+      onClose: () => {},
+      onDead: () => {},
+      maxFrameBytes: 1024,
+      initialWindowBytes: 1_000_000,
+      schedule: () => ({ cancel: () => {} }),
+    })
+    agent = createMuxSession({
+      role: 'agent',
+      sendWire: (f) => relay.onWire(f),
+      onOpen: () => {},
+      onData: (_id, payload) => (delivered = payload),
+      onClose: () => {},
+      onDead: () => {},
+      maxFrameBytes: 1024,
+      initialWindowBytes: 1_000_000,
+      schedule: () => ({ cancel: () => {} }),
+    })
+    const open: MuxOpen = { streamId: 0, subdomain: 'alice', requestPath: '/', originHeader: 'o', remoteAddrHash: 'h', capabilityTokenRef: 'j' }
+    relay.openStream(open).writeData(marker)
+    expect(delivered).not.toBeNull()
+    expect([...delivered!]).toEqual([...marker]) // byte-identical, opaque
+  })
+})