Chat README: request telemetry (telemetry_samples, one-minute aggregates, 14 days) (#100)

ddiff --git a/README.md b/README.md
iindex 2b37e9a..12709d1 100644
---- a/README.md
++++ b/README.md
@@@ -390,6 +390,13 @@ counters.
  Production: `deploy/systemd/openvibe-chat.service`, `deploy/nginx/openvibe.live-chat.locations.conf`,
  `/etc/openvibe/chat.env`.
  
++Request telemetry: counted by route template, method and status class, not raw URL; `/shared` files,
++static assets, health, readiness and `/metrics` are not counted. One `http.request` sample per key a
++minute, plus the active-requests, p95 latency and event-loop-lag gauges, goes to `telemetry_samples`
++(openvibe-sdk 0.46, `platform.telemetry-sample@1`; `migrations/0011_telemetry.sql`), pruned daily past
++14 days. `server/app.js` mounts the SDK's `telemetryMiddleware` (a no-op until init); `server/index.js`
++calls `telemetry.init()` at production start, runs the retention and flushes on stop.
++
  ### Per-actor limits
  
  The REST API also limits who calls it (`server/net/actor-limits.js`, openvibe-sdk/limits, roadmap