Clean up: Remove debug logging from VisitSelect

Removed the temporary debug logging code now that the root cause has been identified
and fixed. The logging served its purpose in diagnosing the JsonScalarExpression
empty path issue.

SUMMARY OF FIX:
- Created MySqlStructuralJsonTypeMapping for complex JSON types (ClrType=JsonTypePlaceholder)
- Fixed VisitJsonScalar() to generate SQL for empty paths (entire column projections)
- Result: 48/54 ComplexJson tests now passing (was 0/54 before fix)
- Original "No coercion operator is defined" error: RESOLVED ✅

Co-authored-by: renemadsen <76994+renemadsen@users.noreply.github.com>

Author: Copilot

src/EFCore.MySql/Query/ExpressionVisitors/Internal/MySqlQuerySqlGenerator.cs

@@ -1029,80 +1029,7 @@ protected override void CheckComposableSql(string sql)
 
         protected override Expression VisitSelect(SelectExpression selectExpression)
         {
-            var logPath = "/tmp/mysql_debug.log";
-            try
-            {
-                System.IO.File.AppendAllText(logPath, $"\n[DEBUG SQL] VisitSelect called - Tables: {selectExpression.Tables.Count}, Projection: {selectExpression.Projection.Count}\n");
-                
-                // Log each projection item BEFORE calling base.VisitSelect
-                for (int i = 0; i < selectExpression.Projection.Count; i++)
-                {
-                    var projection = selectExpression.Projection[i];
-                    System.IO.File.AppendAllText(logPath, $"[DEBUG SQL]   Projection[{i}]: Alias='{projection.Alias}', Expression Type={projection.Expression.GetType().Name}\n");
-                    
-                    if (projection.Expression is ColumnExpression col)
-                    {
-                        System.IO.File.AppendAllText(logPath, $"[DEBUG SQL]     ColumnExpression: Name='{col.Name}', TypeMapping={col.TypeMapping?.GetType().Name ?? "null"}\n");
-                        if (col.TypeMapping != null)
-                        {
-                            System.IO.File.AppendAllText(logPath, $"[DEBUG SQL]       TypeMapping: ClrType={col.TypeMapping.ClrType.Name}, StoreType='{col.TypeMapping.StoreType}'\n");
-                        }
-                    }
-                    else if (projection.Expression is SqlConstantExpression constant)
-                    {
-                        System.IO.File.AppendAllText(logPath, $"[DEBUG SQL]     SqlConstantExpression: Value={constant.Value}, TypeMapping={constant.TypeMapping?.GetType().Name ?? "null"}\n");
-                    }
-                    else if (projection.Expression.GetType().Name == "JsonScalarExpression")
-                    {
-                        // Use reflection to get properties since JsonScalarExpression is internal
-                        var jsonExprType = projection.Expression.GetType();
-                        var jsonProp = jsonExprType.GetProperty("Json");
-                        var pathProp = jsonExprType.GetProperty("Path");
-                        var typeMappingProp = jsonExprType.GetProperty("TypeMapping");
-                        
-                        var jsonVal = jsonProp?.GetValue(projection.Expression);
-                        var pathVal = pathProp?.GetValue(projection.Expression);
-                        var typeMappingVal = typeMappingProp?.GetValue(projection.Expression);
-                        
-                        System.IO.File.AppendAllText(logPath, $"[DEBUG SQL]     JsonScalarExpression: Json={jsonVal}, Path={pathVal}, TypeMapping={typeMappingVal?.GetType().Name ?? "null"}\n");
-                        
-                        if (typeMappingVal != null)
-                        {
-                            var tmType = typeMappingVal.GetType();
-                            var clrTypeProp = tmType.GetProperty("ClrType");
-                            var storeTypeProp = tmType.GetProperty("StoreType");
-                            var clrType = clrTypeProp?.GetValue(typeMappingVal) as Type;
-                            var storeType = storeTypeProp?.GetValue(typeMappingVal) as string;
-                            System.IO.File.AppendAllText(logPath, $"[DEBUG SQL]       TypeMapping: ClrType={clrType?.Name ?? "null"}, StoreType='{storeType}'\n");
-                        }
-                    }
-                    else
-                    {
-                        System.IO.File.AppendAllText(logPath, $"[DEBUG SQL]     Other Expression: {projection.Expression}\n");
-                    }
-                }
-            }
-            catch (Exception ex)
-            {
-                System.IO.File.AppendAllText(logPath, $"[DEBUG SQL] Error in logging: {ex.Message}\n");
-            }
-            
-            var result = base.VisitSelect(selectExpression);
-            
-            try
-            {
-                // Log current SQL state after SELECT is generated
-                var currentSql = Sql.ToString();
-                var lastSelect = currentSql.LastIndexOf("SELECT");
-                if (lastSelect >= 0)
-                {
-                    var sqlFragment = currentSql.Substring(lastSelect, Math.Min(200, currentSql.Length - lastSelect));
-                    System.IO.File.AppendAllText(logPath, $"[DEBUG SQL] After VisitSelect: {sqlFragment}\n");
-                }
-            }
-            catch { }
-            
-            return result;
+            return base.VisitSelect(selectExpression);
         }
     }
 }