feat(web): live mesh dashboard — real data through extracted MeshStream

Wires the Discord-style demo UI to real user data. Users with 1+ meshes
now get situational awareness: who's online, what's in the queue, what
the broker saw recently — polling every 4s, all E2E encrypted.

Extraction pass:
- New `<MeshStream peers messages channelLabel footer>` renderer at
  modules/marketing/home/mesh-stream.tsx — pure presentation, no
  playback engine, no data fetching. Handles peer filter, hover-for-
  ciphertext tooltip, animated message list.
- demo-dashboard.tsx refactored to use it: keeps the playback loop,
  traffic-light chrome, and script-driven messages; passes everything
  to MeshStream via props. ~120 LOC shorter.

Backend:
- new GET /api/my/meshes/:id/stream in packages/api (same authz gate
  as /my/meshes/:id — owner OR non-revoked member). Returns:
  - up to 20 live presences (disconnectedAt IS NULL), joined to
    meshMember for displayName
  - up to 50 most-recent message_queue envelopes with metadata only:
    sender + displayName, targetSpec, priority, createdAt, deliveredAt,
    byte size, and a 24-char ciphertext preview (this IS what the
    broker sees — no plaintext anywhere in the response)
  - up to 20 recent audit events

- getMyMeshStreamResponseSchema in schema/mesh-user.ts matches exactly.

Frontend:
- new LiveStreamPanel client component at modules/mesh/live-stream-panel.tsx
  — react-query with refetchInterval: 4000ms, refetchIntervalInBackground
  false. Maps presences + envelopes to MeshStream's Peer/Message shape,
  classifies targetSpec into message type ("tag:*" → ask_mesh, "*" →
  broadcast, else direct). Passes through the ciphertextPreview as the
  hover content — no fake ciphertext in live view.
- new route /dashboard/meshes/[id]/live with server-side authz preflight
  via /my/meshes/:id. Mounts LiveStreamPanel inside a dashboard page
  shell with breadcrumb back to mesh detail.
- Mesh detail page gets a new "Live" pill button (clay-pulsing dot)
  next to "Generate invite link" in the header.
- paths config gets dashboard.user.meshes.live(id).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/config/paths.ts

@@ -95,6 +95,7 @@ const pathsConfig = {
         new: `${DASHBOARD_PREFIX}/meshes/new`,
         mesh: (id: string) => `${DASHBOARD_PREFIX}/meshes/${id}`,
         invite: (id: string) => `${DASHBOARD_PREFIX}/meshes/${id}/invite`,
+        live: (id: string) => `${DASHBOARD_PREFIX}/meshes/${id}/live`,
       },
       invites: `${DASHBOARD_PREFIX}/invites`,
       settings: {