Fix inference of type of Model::find() to base on framework behavior

[paulbalandan]

Fixes#7

This is based on https://github.com/codeigniter4/CodeIgniter4/blob/79c1b2f7868642d3de9342817ccad93835765a91/system/Model.php#L182-L203.

To fix that category_id is inferred as mixed, the array shape should be defined, something like:

 /**
* Recalculate stats for thread.
*
+ * @param array{data: array{category_id: int}} $data+ *
* @throws ReflectionException
*/
protected function recalculateStats(array $data)

[MGatner]

Looks good!