chore(sonar): hoist constant array literals to static readonly fields (CA1861)

Applied via `dotnet format analyzers --diagnostics CA1861 --severity info`,
plus manual cleanup:

- Renamed two cryptic fixer-generated field names:
  - QueryBreakdownCollection.stringArray -> SnowflakeFunctionNames (and
    inlined the now-redundant local alias)
  - ExpressionObjectTests.arg2 -> NotInValues
- Deduped three identical `separator = ['\r','\n']` fields the fixer
  emitted in the same test class (kept the first declaration; the other
  two test methods now reuse it).

8 files touched.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Strata.SqlTools.Snowflake/Breakdowns/QueryBreakdownCollection.cs

@@ -182,6 +182,15 @@ public class QueryBreakdownCollection : SqlServer.QueryBreakdownCollectionBase<Q
         });
     }
 
+    private static readonly string[] SnowflakeFunctionNames =
+    [
+        "PARSE_JSON", "OBJECT_INSERT", "ARRAY_CONSTRUCT", "ARRAY_AGG",
+        "FLATTEN", "GET_PATH", "TRY_PARSE_JSON", "JSON_EXTRACT_PATH_TEXT",
+        "JSON_EXTRACT_PATH_WITH_DEFAULT", "HASHAGGREGATE", "LISTAGG",
+        "APPROX_COUNT_DISTINCT", "APPROX_PERCENTILE", "GREATEST", "LEAST",
+        "NULLIF", "ZEROIFNULL", "STRTOK", "SPLIT_PART", "PIVOT", "UNPIVOT"
+    ];
+
     /// <summary>
     /// Filters queries that use Snowflake functions (PARSE_JSON, OBJECT_INSERT, ARRAY, etc.).
     /// </summary>
@@ -191,17 +200,7 @@ public class QueryBreakdownCollection : SqlServer.QueryBreakdownCollectionBase<Q
         return QueryBreakdownList.Where(q =>
         {
             var sql = q.GetSql().ToUpperInvariant();
-
-            var snowflakeFunctions = new[]
-            {
-                "PARSE_JSON", "OBJECT_INSERT", "ARRAY_CONSTRUCT", "ARRAY_AGG",
-                "FLATTEN", "GET_PATH", "TRY_PARSE_JSON", "JSON_EXTRACT_PATH_TEXT",
-                "JSON_EXTRACT_PATH_WITH_DEFAULT", "HASHAGGREGATE", "LISTAGG",
-                "APPROX_COUNT_DISTINCT", "APPROX_PERCENTILE", "GREATEST", "LEAST",
-                "NULLIF", "ZEROIFNULL", "STRTOK", "SPLIT_PART", "PIVOT", "UNPIVOT"
-            };
-
-            return snowflakeFunctions.Any(func => sql.Contains(func));
+            return SnowflakeFunctionNames.Any(func => sql.Contains(func));
         });
     }
 

src/Strata.SqlTools.SqlBreakdown/Utilities/SqlUtils.cs

@@ -23,6 +23,7 @@ public static partial class SqlUtils
     public const string DATETIME_INSERT_FORMAT = "yyyyMMdd HH:mm:ss";
 
     private const string DEFAULT_SCHEMA = "dbo";
+    private static readonly char[] separator = new[] { ',' };
 
     #region SQL String Manipulation
 
@@ -34,7 +35,7 @@ public static partial class SqlUtils
     public static string StripColumnTableAlias(string sql)
     {
         // Break sql into words and remove "abc." from each column
-        string[] commaWords = sql.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
+        string[] commaWords = sql.Split(separator, StringSplitOptions.RemoveEmptyEntries);
         var newParts = new List<string>();
 
         foreach (string commaWord in commaWords)

src/Strata.SqlTools.SqlServer/Statements/StatementParser.cs

@@ -21,6 +21,7 @@ public class StatementParser
     public const string KeywordGroupBy = "GROUP BY";
     public const string KeywordHaving = "HAVING";
     public const string KeywordOrderBy = "ORDER BY";
+    private static readonly char[] separator = new[] { '\r', '\n' };
 
     #endregion
 
@@ -50,7 +51,7 @@ public class StatementParser
         // Replace multiple spaces/tabs with single space, but preserve newlines for comment handling
         sql = Regex.Replace(sql, @"[ \t]+", " ", RegexOptions.None, RegexDefaults.MatchTimeout);
         // Remove leading/trailing whitespace from each line
-        var lines = sql.Split(new[] { '\r', '\n' }, StringSplitOptions.None);
+        var lines = sql.Split(separator, StringSplitOptions.None);
         sql = string.Join("\n", lines.Select(line => line.Trim()));
         return sql.Trim();
     }