fix: LIKE on INTEGER columns fails in PostgreSQL

[ivan95mq]

Summary

When using LIKE or NOT LIKE operators on INTEGER columns (e.g. idproyecto), PostgreSQL throws a type error because LOWER() cannot be applied to integer types:

operator does not exist: integer ~~ unknown

This happens in the sqlOperatorLike method in Core/Where.php.

Fix

Wrapping the column reference in CONCAT(col, '') forces an implicit cast to text, making LOWER() work correctly on any column type:

```php
// Before
'LOWER(' . self::sqlColumn($field) . ') ' . $operator

// After
'LOWER(CONCAT(' . self::sqlColumn($field) . ",'')) " . $operator
```

Compatibility

• PostgreSQL: fixes the type error on integer columns
• MySQL: `CONCAT()` is fully supported, no behavior change on text columns

Use case

This fixes autocomplete searches on integer fields — for example, searching projects by ID in sales/purchase documents when using the Proyectos plugin (`idproyecto LIKE '%123%'`).