feat: add fetchRaw

[fpnuseis]

This PR continues the work from the abandoned PR #975:
https://github.com/ppetzold/nestjs-paginate/pull/975

The original PR introduced raw-fetch support but also proposed a new count-related config option.
Since the current version of the library already provides buildCountQuery, which fully satisfies the count customization needs, the additional count config was not included.

[Copilot]

Pull request overview

This PR introduces a new fetchRaw configuration option to enable retrieving raw SQL results from TypeORM queries, which is particularly useful for aggregated or computed fields.

Key changes:

• Added fetchRaw boolean option to PaginateConfig interface
• Updated pagination logic to use getRawMany() instead of getMany() when fetchRaw is enabled
• Added comprehensive test with SQL aggregates using a new SaleEntity for validation

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/paginate.ts	Adds fetchRaw config option and implements conditional logic to use getRawMany() across different pagination scenarios (standard pagination, cursor pagination, and non-paginated queries)
src/paginate.spec.ts	Adds test infrastructure (repository, entity imports) and a comprehensive test case demonstrating fetchRaw with SQL aggregates and custom count query
src/tests/sale.entity.ts	Introduces a new test entity for sales data with decimal columns to support aggregate function testing
README.md	Documents the new fetchRaw configuration option with clear description, use cases, and important notes about SQL aliases

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[fpnuseis]

@ppetzold
I need help.
buildCountQuery currently takes a cloned QueryBuilder, adjusts it, and returns another QueryBuilder.
Later, the library calls .getCount() on that returned builder.

The problem is: TypeORM’s getCount() cannot correctly count grouped results.
Even if the user sets their own select, groupBy, or distinct, getCount() internally rebuilds the count query and ends up counting base table rows instead of grouped rows.

Because of this limitation, I’m considering redesigning the buildCountQuery API so that:

Instead of returning a QueryBuilder,

buildCountQuery returns a number (or a Promise),
allowing the user to execute their own count query freely.

For example:

buildCountQuery: async (qb) => {
    const sql = qb.orderBy().limit().offset().take().skip().getQuery();

    const result = await qb
        .createQueryBuilder()
        .select('COUNT(*)', 'total_rows')
        .from(`(${sql})`, 'query_count')
        .setParameters(qb.getParameters())
        .getRawOne();

    return Number(result.total_rows);
}

This makes it possible for users to:

• Run raw subquery counts
• Count grouped results correctly
• Avoid TypeORM’s restrictive getCount() behavior
• Fully customize the count logic for raw/aggregate queries

What do you think about this redesign?
I’m also open to different ideas if you have alternative suggestions.