Remove unnecessary modularization from auto-increment overflow fix

Inlined bounds checking logic directly where used instead of helper function:
- Removed canIncrementAutoIncVal() helper function from table.go
- Inlined logic in table_editor.go Insert method (2 locations)
- Inlined logic in table.go AddColumn method (1 location)
- Used existing colType.Convert() pattern for type checking

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: elianddb

memory/table.go

@@ -1147,11 +1147,6 @@ func (t *Table) PeekNextAutoIncrementValue(ctx *sql.Context) (uint64, error) {
 	return data.autoIncVal, nil
 }
 
-func canIncrementAutoIncVal(ctx *sql.Context, colType sql.Type, currentVal uint64) bool {
-	nextVal := currentVal + 1
-	_, inRange, err := colType.Convert(ctx, nextVal)
-	return err == nil && inRange == sql.InRange
-}
 
 // GetNextAutoIncrementValue gets the next auto increment value for the memory table the increment.
 func (t *Table) GetNextAutoIncrementValue(ctx *sql.Context, insertVal interface{}) (uint64, error) {
@@ -1262,7 +1257,8 @@ func addColumnToSchema(ctx *sql.Context, data *TableData, newCol *sql.Column, or
 			data.autoIncVal = 0
 		}
 
-		if canIncrementAutoIncVal(ctx, newCol.Type, data.autoIncVal) {
+		nextVal := data.autoIncVal + 1
+		if _, inRange, err := newCol.Type.Convert(ctx, nextVal); err == nil && inRange == sql.InRange {
 			data.autoIncVal++
 		}
 	}

memory/table_editor.go

@@ -191,11 +191,13 @@ func (t *tableEditor) Insert(ctx *sql.Context, row sql.Row) error {
 				return err
 			}
 			t.ea.TableData().autoIncVal = v.(uint64)
-			if canIncrementAutoIncVal(ctx, autoCol.Type, v.(uint64)) {
+			nextVal := v.(uint64) + 1
+			if _, inRange, err := autoCol.Type.Convert(ctx, nextVal); err == nil && inRange == sql.InRange {
 				t.ea.TableData().autoIncVal++
 			}
 		} else if cmp == 0 {
-			if canIncrementAutoIncVal(ctx, autoCol.Type, t.ea.TableData().autoIncVal) {
+			nextVal := t.ea.TableData().autoIncVal + 1
+			if _, inRange, err := autoCol.Type.Convert(ctx, nextVal); err == nil && inRange == sql.InRange {
 				t.ea.TableData().autoIncVal++
 			}
 		}