Introduce sort & filters

[gpunto]

• Moving sort from feeds to core
• Introducing type-safe filters (different from what we currently have in feeds)

I'll migrate feeds to this impl after releasing

[Copilot]

Pull Request Overview

This PR introduces a comprehensive filtering and sorting system for the Stream Android Core library. The implementation provides type-safe APIs for building filters and sorts that can be used both for local operations and remote API requests.

• Introduces filter system with operators like equal, greater than, in, query, etc.
• Adds sorting functionality with configurable directions and composite comparators
• Provides type-safe field definitions for filters and sorts with remote API mapping

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
FilterToRequestTest.kt	Comprehensive test suite validating filter-to-request conversion
FilterOperator.kt	Enum defining all supported filter operators with API mapping
SortField.kt	Interface for sortable fields with local and remote capabilities
SortDirection.kt	Enum for ascending/descending sort directions
SortComparator.kt	Comparator classes for local sorting with type erasure support
Sort.kt	Main sort configuration class combining field and direction
Filters.kt	Utility class and extension functions for building filters
FilterField.kt	Base interface for filterable fields
Filter.kt	Core filter interfaces and conversion logic
Configuration.kt	License URL correction

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