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);

channel_analytics/contracts.py

@@ -168,6 +168,7 @@ def build_dashboard(
     source_monthly_sha256: str,
     channel_names: Iterable[str],
     facts: Iterable[AggregatedRoomFact],
+    min_arrival_date: Optional[str] = None,
 ) -> Dict[str, Any]:
     validate_month_key(month_key)
     names = tuple(channel_names)
@@ -213,6 +214,7 @@ def build_dashboard(
         "version": DASHBOARD_VERSION,
         "month_key": month_key,
         "updated_at": updated_at,
+        "min_arrival_date": min_arrival_date,
         "max_arrival_date": max_arrival_date,
         "source_monthly_sha256": source_monthly_sha256,
         "overall": {

channel_analytics/postgres.py

@@ -28,6 +28,7 @@ FALLBACK_DATABASE_ENV = "ARR_DATABASE_URL"
 
 CURRENT_REPORT_SQL = """
 SELECT
+    min(current_version.business_date) AS data_start_date,
     max(current_version.business_date) AS as_of_date,
     max(current_version.activated_at) AS updated_at,
     count(*) AS daily_version_count
@@ -143,6 +144,7 @@ class ChannelManifestItem:
 class ReportContext:
     period_start: date
     period_end: date
+    data_start_date: date
     as_of_date: date
     activated_at: datetime
     source_projection_sha256: str
@@ -303,11 +305,12 @@ class PostgresAnalyticsRepository:
     ) -> ReportContext:
         cursor.execute(CURRENT_REPORT_SQL, (period_start, period_end))
         row = cursor.fetchone()
-        if not row or row[0] is None or _integer(row[2], "daily_version_count") == 0:
+        if not row or row[0] is None or row[1] is None or _integer(row[3], "daily_version_count") == 0:
             raise AnalyticsMonthNotFound()
-        as_of_date = _date(row[0], "as_of_date")
-        activated_at = _datetime(row[1])
-        daily_version_count = _integer(row[2], "daily_version_count")
+        data_start_date = _date(row[0], "data_start_date")
+        as_of_date = _date(row[1], "as_of_date")
+        activated_at = _datetime(row[2])
+        daily_version_count = _integer(row[3], "daily_version_count")
 
         cursor.execute(REPORT_PIN_COUNT_SQL, (period_start, period_end))
         identity_rows = list(cursor.fetchall())
@@ -348,6 +351,7 @@ class PostgresAnalyticsRepository:
         return ReportContext(
             period_start=period_start,
             period_end=period_end,
+            data_start_date=data_start_date,
             as_of_date=as_of_date,
             activated_at=activated_at,
             source_projection_sha256=_projection_sha256(identity_rows),
@@ -419,6 +423,7 @@ class PostgresAnalyticsRepository:
                 source_monthly_sha256=context.source_projection_sha256,
                 channel_names=(item.worksheet for item in context.channels),
                 facts=facts,
+                min_arrival_date=context.data_start_date.isoformat(),
             )
         except AnalyticsError:
             raise