feat: allow custom query builders via connection

[binaryfire]

Summary

Model, Pivot, and MorphPivot now delegate to $connection->query() when creating base query builders, instead of hardcoding new QueryBuilder(...).

This enables custom connections to provide custom query builders with additional methods without requiring macros or upstream PRs.

Laravel does it this way as well.

Changes

Override newBaseQueryBuilder() in:

• Hypervel\Database\Eloquent\Model
• Hypervel\Database\Eloquent\Relations\Pivot
• Hypervel\Database\Eloquent\Relations\MorphPivot

protected function newBaseQueryBuilder()
{
    /** @var \Hyperf\Database\Connection $connection */
    $connection = $this->getConnection();

    return $connection->query();
}

Usage

// Custom connection with custom query builder
class PostgresConnection extends BasePostgresConnection
{
    public function query(): Builder
    {
        return new CustomBuilder($this, $this->getQueryGrammar(), $this->getPostProcessor());
    }
}

// Register it
Connection::resolverFor('pgsql', fn (...$args) => new PostgresConnection(...$args));

// Now all models use the custom builder
User::query()->whereSomeCustomMethod('xxxxx')->get();

Backwards Compatibility

No breaking changes. Connection::query() already does the same instantiation - now we just delegate to it instead of duplicating.

Tests

Added NewBaseQueryBuilderTest with 3 tests verifying Model, Pivot, and MorphPivot all delegate to the connection's query() method.

[binaryfire]

Closing. Will be part of a bigger database PR