refactor: add reverse configuration and enhance transformation logic for PostgreSQL to SQL Server migration

internal/app/etl/transformers/plan.go

@@ -64,12 +64,28 @@ func computePostgresTransformationPlan(columns []models.ColumnType) []etl.Column
 
 	for i, col := range columns {
 		switch col.SystemType() {
+		case "int2", "int4", "int8", "integer", "smallint", "bigint":
+			plan = append(plan, etl.ColumnTransformPlan{
+				Index: i,
+				Fn: func(v any) (any, error) {
+					if v64, ok := ToInt64(v); ok {
+						return v64, nil
+					}
+					return v, nil
+				},
+			})
+
 		case "uuid":
 			plan = append(plan, etl.ColumnTransformPlan{
 				Index: i,
 				Fn: func(v any) (any, error) {
-					if b, ok := v.([]byte); ok && b != nil {
-						return bigEndianToMssqlUuid(b)
+					switch b := v.(type) {
+					case []byte:
+						if b != nil {
+							return bigEndianToMssqlUuid(b)
+						}
+					case [16]byte:
+						return bigEndianToMssqlUuid(b[:])
 					}
 					return v, nil
 				},

internal/app/etl/transformers/utils.go

@@ -82,31 +82,9 @@ func ewkbToMssqlGeo(ewkb []byte, isGeography bool) ([]byte, error) {
 	if len(ewkb) < 5 {
 		return nil, errors.New("Invalid ewkb")
 	}
-
-	var byteOrder binary.ByteOrder
-	if ewkb[0] == 0 {
-		byteOrder = binary.BigEndian
-	} else {
-		byteOrder = binary.LittleEndian
-	}
-
-	wkbType := byteOrder.Uint32(ewkb[1:5])
-
-	var wkb []byte
-	if wkbType&sridFlag != 0 {
-		if len(ewkb) < 9 {
-			return nil, errors.New("Invalid ewkb: SRID flag set but data too short")
-		}
-		clearType := wkbType &^ uint32(sridFlag)
-		wkb = make([]byte, len(ewkb)-4)
-		wkb[0] = ewkb[0]
-		byteOrder.PutUint32(wkb[1:5], clearType)
-		copy(wkb[5:], ewkb[9:])
-	} else {
-		wkb = ewkb
-	}
-
-	return mssqlclrgeo.WkbToUdtGeo(wkb, isGeography)
+	// mssqlclrgeo reads the SRID flag and bytes directly from EWKB,
+	// so no pre-processing needed — pass through as-is.
+	return mssqlclrgeo.WkbToUdtGeo(ewkb, isGeography)
 }
 
 func ToInt64(v any) (int64, bool) {