Fix INSERT IGNORE enum zero handling in strict mode

Allow uint16 enum indices to be converted without strict mode validation.
This fixes INSERT IGNORE behavior where stored uint16(0) values should
display as empty strings, matching MySQL behavior exactly.

Resolves the (unknown) error during SELECT after INSERT IGNORE.

Author: elianddb

sql/types/enum.go

@@ -182,7 +182,10 @@ func (t EnumType) Convert(ctx context.Context, v interface{}) (interface{}, sql.
 	case int16:
 		return t.Convert(ctx, int(value))
 	case uint16:
-		return t.Convert(ctx, int(value))
+		// uint16 values are stored enum indices - allow them without strict mode validation
+		if _, ok := t.At(int(value)); ok {
+			return value, sql.InRange, nil
+		}
 	case int32:
 		return t.Convert(ctx, int(value))
 	case uint32: