fix(generator): устранён флаки runtime-гейта стыка backfill/live

- Зачем:
  - гейт generated-history-runtime-check падал через раз: docker compose
    stop убивал генератор SIGKILL'ом посреди batch (SIGTERM не ловился),
    непарные строки маскировались под «смену фактуры» (задача 20).
- Что:
  - генератор грациозно завершается по SIGTERM: текущий batch дописывается
    во все топики с flush и записью history; compose даёт минуту grace.
  - runtime-check ждёт пересекающий визит в STG (предусловие проверки),
    seam-check получил precheck непарных live-строк; в STG-запросах
    закреплён 'UTC' против сдвига наивных меток в поясе сервера.
  - контрактные тесты усилены, задача 20 закрыта, блокер задачи 13 снят.
- Проверка:
  - тесты: 192 passed (generator), 21 passed (контракты);
  - стенд: 3 подряд зелёных make generated-history-runtime-check;
    красный сценарий (искажение referer_url пересекающего визита) валит
    гейт прежним сообщением при нулевых непарных счётчиках.

scripts/check_generated_analytics.sh

@@ -335,6 +335,114 @@ if [[ "${should_check_live_seam}" == "1" ]]; then
   echo ""
   echo "=== Проверка ClickHouse: стык backfill/live в DDS ==="
 
+  live_pairing_query="
+WITH
+    parseDateTime64BestEffort('${manifest_model_t_end}', 6, 'UTC') AS t_end,
+    t_end + INTERVAL ${GEN_LIVE_CHECK_MINUTES} MINUTE AS t_live_end,
+    live_browser AS (
+        SELECT
+            toUUIDOrNull(JSONExtractString(raw, 'event_id')) AS event_id,
+            toUUIDOrNull(JSONExtractString(raw, 'click_id')) AS click_id
+        FROM stg.browser_raw
+        WHERE parseDateTime64BestEffortOrNull(
+                  JSONExtractString(raw, 'event_timestamp'), 6, 'UTC'
+              ) >= t_end
+          AND parseDateTime64BestEffortOrNull(
+                  JSONExtractString(raw, 'event_timestamp'), 6, 'UTC'
+              ) < t_live_end
+          AND event_id IS NOT NULL
+          AND click_id IS NOT NULL
+        GROUP BY event_id, click_id
+    ),
+    live_click_ids AS (
+        SELECT click_id
+        FROM live_browser
+        GROUP BY click_id
+    ),
+    browser_counts AS (
+        SELECT click_id, count() AS browser_rows
+        FROM
+        (
+            SELECT
+                toUUIDOrNull(JSONExtractString(raw, 'event_id')) AS event_id,
+                toUUIDOrNull(JSONExtractString(raw, 'click_id')) AS click_id
+            FROM stg.browser_raw
+            WHERE event_id IS NOT NULL AND click_id IS NOT NULL
+            GROUP BY event_id, click_id
+        )
+        WHERE click_id IN (SELECT click_id FROM live_click_ids)
+        GROUP BY click_id
+    ),
+    location_ids AS (
+        SELECT toUUIDOrNull(JSONExtractString(raw, 'event_id')) AS event_id
+        FROM stg.location_raw
+        WHERE event_id IS NOT NULL
+        GROUP BY event_id
+    ),
+    device_counts AS (
+        SELECT
+            toUUIDOrNull(JSONExtractString(raw, 'click_id')) AS click_id,
+            count() AS device_rows
+        FROM stg.device_raw
+        WHERE click_id IS NOT NULL
+          AND click_id IN (SELECT click_id FROM live_click_ids)
+        GROUP BY click_id
+    ),
+    geo_counts AS (
+        SELECT
+            toUUIDOrNull(JSONExtractString(raw, 'click_id')) AS click_id,
+            count() AS geo_rows
+        FROM stg.geo_raw
+        WHERE click_id IS NOT NULL
+          AND click_id IN (SELECT click_id FROM live_click_ids)
+        GROUP BY click_id
+    )
+SELECT
+    (SELECT count() FROM live_browser) AS live_browser_rows,
+    (
+        SELECT count()
+        FROM live_browser AS b
+        LEFT JOIN location_ids AS l ON l.event_id = b.event_id
+        WHERE l.event_id IS NULL
+    ) AS unpaired_location_rows,
+    (
+        SELECT ifNull(sum(if(
+            b.browser_rows > ifNull(d.device_rows, 0),
+            b.browser_rows - ifNull(d.device_rows, 0),
+            0
+        )), 0)
+        FROM browser_counts AS b
+        LEFT JOIN device_counts AS d ON d.click_id = b.click_id
+    ) AS unpaired_device_rows,
+    (
+        SELECT ifNull(sum(if(
+            b.browser_rows > ifNull(g.geo_rows, 0),
+            b.browser_rows - ifNull(g.geo_rows, 0),
+            0
+        )), 0)
+        FROM browser_counts AS b
+        LEFT JOIN geo_counts AS g ON g.click_id = b.click_id
+    ) AS unpaired_geo_rows
+SETTINGS join_use_nulls = 1
+FORMAT TabSeparated"
+
+  live_pairing="$(ch_query "${live_pairing_query}")"
+  IFS=$'\t' read -r live_browser_rows unpaired_location_rows unpaired_device_rows unpaired_geo_rows <<< "${live_pairing}"
+
+  [[ "${live_browser_rows}" =~ ^[0-9]+$ ]] \
+    && [[ "${unpaired_location_rows}" =~ ^[0-9]+$ ]] \
+    && [[ "${unpaired_device_rows}" =~ ^[0-9]+$ ]] \
+    && [[ "${unpaired_geo_rows}" =~ ^[0-9]+$ ]] \
+    || fail "не удалось прочитать пары live-строк"
+  if (( unpaired_location_rows > 0 || unpaired_device_rows > 0 || unpaired_geo_rows > 0 )); then
+    fail "непарные live-строки: location=${unpaired_location_rows}, device=${unpaired_device_rows}, geo=${unpaired_geo_rows} из browser=${live_browser_rows}"
+  fi
+
+  echo "live_browser_rows=${live_browser_rows}"
+  echo "unpaired_location_rows=${unpaired_location_rows}"
+  echo "unpaired_device_rows=${unpaired_device_rows}"
+  echo "unpaired_geo_rows=${unpaired_geo_rows}"
+
   seam_duplicates_query="
 WITH
     toDateTime64('${CH_MODEL_T0}', 6) AS t0,