Update Eloquent Builder references to use Contracts for improved type consistency

[kettasoft]

Summary

This PR replaces all usages of:

use Illuminate\Database\Eloquent\Builder;

with:

use Illuminate\Contracts\Database\Eloquent\Builder;

across the entire package.

The change ensures that the package can accept any Eloquent builder–compatible instance, not only the base Illuminate\Database\Eloquent\Builder.

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Motivation

The previous implementation strictly type-hinted Illuminate\Database\Eloquent\Builder, which caused type conflicts when passing relationship builders such as HasMany, HasOne, or BelongsTo into Filterable::setBuilder().

Example of the issue:

$hasMany = User::find(1)->posts();   // This returns a HasMany instance
Filterable::create()->setBuilder($hasMany);

This throws an error because:

• posts() returns an instance of Illuminate\Database\Eloquent\Relations\HasMany
• HasMany implements the contract Illuminate\Contracts\Database\Eloquent\Builder
• but does not extend the concrete class Illuminate\Database\Eloquent\Builder
• therefore the type-hint rejected it as invalid, even though it is fully compatible from Laravel’s perspective.

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Why the Contract is More Appropriate

Laravel relationship builders implement the contract, not the concrete Builder class.
By switching to the contract:

• We support all Eloquent builder variations.
• The package becomes compatible with relationship queries.
• setBuilder() can accept query builders returned from relationships.
• We avoid forcing consumers to manually access $hasMany->getQuery() or similar workarounds.

This makes the package behave consistently with Laravel's own expectations regarding builder polymorphism.

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Result

After this change:

$hasMany = User::find(1)->posts();
Filterable::create()->setBuilder($hasMany);

works as expected without throwing binding or instantiation errors.

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Additional Notes

• No breaking changes for end-users that already rely on normal model builders.
• Provides broader compatibility for advanced Eloquent usage, especially in complex domain layers.
• Aligns the package more closely with Laravel’s internal type system and contracts-first design philosophy.