Truncate rollup params to second precision for DateTime column

The JDBC driver sends java.sql.Timestamp with nanoseconds as a string
(e.g. '2026-03-15 10:13:58.105931162') which DateTime('UTC') rejects.
Add bucketTimestamp() helper that truncates to seconds for all rollup
query parameters.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/search/ClickHouseSearchEngine.java

@@ -100,9 +100,9 @@ public class ClickHouseSearchEngine implements SearchEngine {
         var conditions = new ArrayList<String>();
         var params = new ArrayList<Object>();
         conditions.add("bucket >= ?");
-        params.add(Timestamp.from(floorToFiveMinutes(from)));
+        params.add(bucketTimestamp(floorToFiveMinutes(from)));
         conditions.add("bucket <= ?");
-        params.add(Timestamp.from(to));
+        params.add(bucketTimestamp(to));
         addScopeFilters(routeId, agentIds, conditions, params);
 
         String where = " WHERE " + String.join(" AND ", conditions);
@@ -140,9 +140,9 @@ public class ClickHouseSearchEngine implements SearchEngine {
         var prevConditions = new ArrayList<String>();
         var prevParams = new ArrayList<Object>();
         prevConditions.add("bucket >= ?");
-        prevParams.add(Timestamp.from(floorToFiveMinutes(prevFrom)));
+        prevParams.add(bucketTimestamp(floorToFiveMinutes(prevFrom)));
         prevConditions.add("bucket <= ?");
-        prevParams.add(Timestamp.from(prevTo));
+        prevParams.add(bucketTimestamp(prevTo));
         addScopeFilters(routeId, agentIds, prevConditions, prevParams);
         String prevWhere = " WHERE " + String.join(" AND ", prevConditions);
 
@@ -166,7 +166,7 @@ public class ClickHouseSearchEngine implements SearchEngine {
         var todayConditions = new ArrayList<String>();
         var todayParams = new ArrayList<Object>();
         todayConditions.add("bucket >= ?");
-        todayParams.add(Timestamp.from(floorToFiveMinutes(todayStart)));
+        todayParams.add(bucketTimestamp(floorToFiveMinutes(todayStart)));
         addScopeFilters(routeId, agentIds, todayConditions, todayParams);
         String todayWhere = " WHERE " + String.join(" AND ", todayConditions);
 
@@ -195,9 +195,9 @@ public class ClickHouseSearchEngine implements SearchEngine {
         var conditions = new ArrayList<String>();
         var params = new ArrayList<Object>();
         conditions.add("bucket >= ?");
-        params.add(Timestamp.from(floorToFiveMinutes(from)));
+        params.add(bucketTimestamp(floorToFiveMinutes(from)));
         conditions.add("bucket <= ?");
-        params.add(Timestamp.from(to));
+        params.add(bucketTimestamp(to));
         addScopeFilters(routeId, agentIds, conditions, params);
 
         String where = " WHERE " + String.join(" AND ", conditions);
@@ -334,6 +334,15 @@ public class ClickHouseSearchEngine implements SearchEngine {
         return Instant.ofEpochSecond(epochSecond - (epochSecond % 300));
     }
 
+    /**
+     * Create a second-precision Timestamp for rollup bucket comparisons.
+     * The bucket column is DateTime('UTC') (second precision); the JDBC driver
+     * sends java.sql.Timestamp with nanoseconds which ClickHouse rejects.
+     */
+    private static Timestamp bucketTimestamp(Instant instant) {
+        return Timestamp.from(instant.truncatedTo(java.time.temporal.ChronoUnit.SECONDS));
+    }
+
     /**
      * Escape special LIKE characters to prevent LIKE injection.
      */