Add db.query.summary and db.operation.name for Text commands

Set db.query.summary as the low-cardinality activity name on all spans.
For Text commands, extract the first SQL verb (SELECT, INSERT, etc.)
and use it as db.operation.name and in the activity name.

Author: fdcastel

src/FirebirdSql.Data.FirebirdClient/Trace/FbActivitySource.cs

@@ -37,7 +37,8 @@ internal static Activity CommandStart(FbCommand command)
 					break;
 
 				case CommandType.Text:
-					activityName = dbName;
+					dbOperationName = ExtractSqlVerb(command.CommandText);
+					activityName = dbOperationName ?? dbName;
 					break;
 
 				default:
@@ -65,6 +66,8 @@ internal static Activity CommandStart(FbCommand command)
 				activity.SetTag("db.operation.name", dbOperationName);
 			}
 
+			activity.SetTag("db.query.summary", activityName);
+
 			if (command.CommandType == CommandType.StoredProcedure)
 			{
 				activity.SetTag("db.stored_procedure.name", command.CommandText);
@@ -119,5 +122,16 @@ internal static void CommandException(Activity activity, Exception exception)
 			activity.SetStatus(ActivityStatusCode.Error, errorDescription);
 			activity.Dispose();
 		}
+
+		static string ExtractSqlVerb(string sql)
+		{
+			if (string.IsNullOrEmpty(sql))
+				return null;
+			var span = sql.AsSpan().TrimStart();
+			var spaceIndex = span.IndexOfAny(' ', '\t', '\n', '\r');
+			if (spaceIndex <= 0)
+				return span.Length > 0 ? span.ToString().ToUpperInvariant() : null;
+			return span.Slice(0, spaceIndex).ToString().ToUpperInvariant();
+		}
 	}
 }