feat: refine web analytics and history views

channel_analytics/README.md

@@ -4,6 +4,9 @@
 
 Read model:
 
+- Dashboard responses now expose the earliest and latest ARRIVAL coverage dates from the same current daily-version
+  snapshot, so the UI can show actual data coverage instead of inferring a full calendar month.
+
 - available months and source pins: `finance.current_daily_versions`;
 - channels/order/counts: `finance.daily_channel_metrics` for those current versions;
 - aggregates and detail: `finance.v_active_daily_facts` (`current + retained` only);