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/metering.test.ts

@@ -0,0 +1,62 @@
+import { describe, test, expect } from 'vitest'
+import { createMemoryStores } from '../src/store/memory.js'
+import { createHostRegistry } from '../src/registry/hosts.js'
+import { createMeteringCollector, MeteringError } from '../src/metering/collect.js'
+import { fingerprint } from '../src/ca/fingerprint.js'
+import { generateEd25519 } from '../src/util/crypto.js'
+import type { NodeIdentity } from '../src/node-auth/identity.js'
+
+const node: NodeIdentity = { nodeId: 'spiffe://relay/node-a' }
+const ACCOUNT = '11111111-1111-4111-8111-111111111111'
+
+async function withHost() {
+  const stores = createMemoryStores()
+  const hosts = createHostRegistry({ hosts: stores.hosts })
+  const { publicKeyRaw } = generateEd25519()
+  const host = await hosts.bindHost({ accountId: ACCOUNT, subdomain: 'alice', agentPubkey: publicKeyRaw, enrollFpr: fingerprint(publicKeyRaw) })
+  const collector = createMeteringCollector({ metering: stores.metering, hosts })
+  return { stores, hosts, host, collector }
+}
+
+describe('T12 metering (INV1/INV3-analog/INV8)', () => {
+  test('ingestSample derives accountId + nodeId server-side; append-only', async () => {
+    const { stores, host, collector } = await withHost()
+    await collector.ingestSample(node, { hostId: host.hostId, concurrentViewers: 3, sampledAt: new Date().toISOString() })
+    const rows = await stores.metering.query(ACCOUNT, '1970-01-01T00:00:00.000Z', '2999-01-01T00:00:00.000Z')
+    expect(rows.length).toBe(1)
+    expect(rows[0]?.accountId).toBe(ACCOUNT)
+    expect(rows[0]?.nodeId).toBe(node.nodeId)
+  })
+
+  test('forged attribution: unknown hostId rejected (cross-tenant metering impossible, INV1)', async () => {
+    const { collector } = await withHost()
+    await expect(
+      collector.ingestSample(node, { hostId: '99999999-9999-4999-8999-999999999999', concurrentViewers: 1, sampledAt: new Date().toISOString() }),
+    ).rejects.toBeInstanceOf(MeteringError)
+  })
+
+  test('pairedHostCount excludes revoked hosts', async () => {
+    const { hosts, host, collector } = await withHost()
+    expect(await collector.pairedHostCount(ACCOUNT)).toBe(1)
+    await hosts.setHostStatus(host.hostId, 'revoked')
+    expect(await collector.pairedHostCount(ACCOUNT)).toBe(0)
+  })
+
+  test('rollupUsage computes viewer peak + viewer-hours over a window', async () => {
+    const { host, collector } = await withHost()
+    const t0 = '2026-06-30T00:00:00.000Z'
+    const t1 = '2026-06-30T01:00:00.000Z'
+    const to = '2026-06-30T02:00:00.000Z'
+    await collector.ingestSample(node, { hostId: host.hostId, concurrentViewers: 2, sampledAt: t0 })
+    await collector.ingestSample(node, { hostId: host.hostId, concurrentViewers: 4, sampledAt: t1 })
+    const usage = await collector.rollupUsage(ACCOUNT, t0, to)
+    expect(usage.viewerPeak).toBe(4)
+    expect(usage.viewerHours).toBeCloseTo(2 * 1 + 4 * 1, 5) // 2 viewers×1h + 4 viewers×1h
+    expect(usage.pairedHostPeak).toBe(1)
+  })
+
+  test('malformed sample → Zod error', async () => {
+    const { collector } = await withHost()
+    await expect(collector.ingestSample(node, { hostId: 'not-a-uuid', concurrentViewers: -1, sampledAt: 'x' })).rejects.toBeInstanceOf(MeteringError)
+  })
+})