fix: improve exception handling in AlertScheduleProvider and MigrateD…

…atabaseV2

AlertScheduleProvider: skip unparseable schedules instead of adding them
to cache as broken objects. A partially-constructed AlertSchedule with no
parsed working hours has unpredictable IsWorkingTime behavior - skipping
is safer than a fallback that silently misfires alerts.

TreeValuesCache.MigrateDatabaseV2: add success/failed counters and log
migration summary so data loss during migration is visible in logs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/server/HSMServer.Core/AlertSchedule/AlertScheduleProvider.cs

@@ -135,14 +135,8 @@ private void LoadSchedulesFromDatabase()
                     }
                     catch (Exception ex)
                     {
-                        _logger.Error(ex, $"Failed to parse alert schedule. Id = {entity.Id}, Name = {entity.Name}. Using raw entity as fallback.");
-                        schedule = new AlertSchedule()
-                        {
-                            Id = new Guid(entity.Id),
-                            Name = entity.Name,
-                            Timezone = entity.Timezone,
-                            Schedule = entity.Schedule,
-                        };
+                        _logger.Error(ex, $"Failed to parse alert schedule. Id = {entity.Id}, Name = {entity.Name}. Schedule will be skipped.");
+                        continue;
                     }
 
                     _cache[schedule.Id] = new CacheEntry

src/server/HSMServer.Core/Cache/TreeValuesCache.cs

@@ -1836,6 +1836,9 @@ private void ApplySensors(List<SensorEntity> sensorEntities, Dictionary<string,
 
         private void MigrateDatabseV2()
         {
+            var success = 0;
+            var failed = 0;
+
             foreach ((byte[] key, byte[] value) in _database.MigrateDatabaseV2())
             {
                 var keyArr = Encoding.UTF8.GetString(key).Split("_");
@@ -1854,15 +1857,23 @@ private void MigrateDatabseV2()
                     catch (Exception ex)
                     {
                         _logger.Error(ex, $"Failed to deserialize sensor value during V2 migration. SensorId = {sensorId}");
+                        failed++;
                         continue;
                     }
 
                     if (!policy.TimeIsUp(val.Time))
                     {
                         _database.AddSensorValue(sensorId, val);
                     }
+
+                    success++;
                 }
             }
+
+            if (failed > 0)
+                _logger.Warn($"V2 migration completed with errors: {success} records migrated, {failed} records skipped due to deserialization errors.");
+            else
+                _logger.Info($"V2 migration completed successfully: {success} records migrated.");
         }
 
         private void ApplyAccessKeys(List<AccessKeyEntity> entities)