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.

agent/src/lifecycle/revocation.ts

@@ -0,0 +1,68 @@
+/**
+ * Revocation + GOAWAY teardown — PLAN_RELAY_AGENT T14 (INV12). Distinguishes a `revoked` GOAWAY
+ * (immediate teardown, NO reconnect) from the graceful `operatorDrain`/`shutdown` reasons
+ * (finish in-flight, reconnect elsewhere) using ONLY the FROZEN §4.1 3-value `GoAwayReason` +
+ * `decodeGoAwayReason` — never a locally-invented numeric mapping (cross-plan drift = silent
+ * INV12 defeat). An unknown numeric code FAILS CLOSED to `revoked`.
+ *
+ * The RevocationState seam is imported from transport/seams.ts (W0), not redeclared. Its
+ * `isRevoked()` is what T10's reconnectLoop consumes (one-way edge, no task cycle).
+ */
+import { decodeGoAwayReason } from 'relay-contracts'
+import type { GoAwayReason } from 'relay-contracts'
+import type { RevocationState, RevokeReason } from '../transport/seams.js'
+
+export type GoAwayAction = 'drain' | 'revoked'
+
+/**
+ * Pure exhaustive map over the FROZEN 3-value union. `operatorDrain`/`shutdown` → drain (reconnect
+ * elsewhere); `revoked` → revoked (stop). No integer literals — the reason is already a label.
+ */
+export function classifyGoAway(reason: GoAwayReason): GoAwayAction {
+  switch (reason) {
+    case 'operatorDrain':
+    case 'shutdown':
+      return 'drain'
+    case 'revoked':
+      return 'revoked'
+  }
+}
+
+export function createRevocationState(onTeardown: () => void): RevocationState {
+  let revoked = false
+  return {
+    isRevoked(): boolean {
+      return revoked
+    },
+    markRevoked(_reason: RevokeReason): void {
+      if (revoked) return
+      revoked = true
+      onTeardown() // close all streams + tunnel immediately
+    },
+  }
+}
+
+/**
+ * Apply a decoded GOAWAY reason to the revocation state. On `revoked`, marks the state revoked
+ * (⇒ teardown + reconnect suppression). Returns the action taken.
+ */
+export function applyGoAway(reason: GoAwayReason, state: RevocationState): GoAwayAction {
+  const action = classifyGoAway(reason)
+  if (action === 'revoked') state.markRevoked('goaway-revoked')
+  return action
+}
+
+/**
+ * Apply a raw GOAWAY wire code. Decodes via the FROZEN decoder; an UNKNOWN code (decoder throws)
+ * FAILS CLOSED to `revoked` (a default that guessed "drain" would defeat INV12).
+ */
+export function applyGoAwayCode(code: number, state: RevocationState): GoAwayAction {
+  let reason: GoAwayReason
+  try {
+    reason = decodeGoAwayReason(code)
+  } catch {
+    state.markRevoked('goaway-revoked') // fail closed
+    return 'revoked'
+  }
+  return applyGoAway(reason, state)
+}