Matches the shape actually asked for and how every other telemetry
counter in this file already works (all-time cumulative via HIncrBy,
no expiry, no per-day key rotation): /metrics now exposes flat
sentinel_errors and sentinel_distinct_sources_est fields instead of a
nested, date-scoped sentinel_today object.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
CLI telemetry showed a growing count of Sentinel rejections but no way
to tell whether they come from one user retrying repeatedly or many
distinct users independently getting blocked.
Adds a per-day Redis HyperLogLog (msdl:telemetry:sentinel_hll:<date>)
seeded from the reporting IP whenever a CLI error contains "Sentinel",
plus a parallel daily counter. /metrics now exposes sentinel_today:
{date, errors_today, distinct_sources_est}. No raw IPs are stored --
HLL is a one-way cardinality estimator, and both keys expire after 48h.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
