feat: add configurable scope name converter

[bunyaminbilenkaratas]

Description

This PR adds a configurable scope name converter to allow customization of how filter property names are converted to Eloquent scope method names.

Changes

• Added scope_name_converter config option with three modes:
  • camel (default): Converts to camelCase (e.g., published_at → publishedAt)
  • none: Uses exact property name without conversion
  • auto: Tries exact method name first, falls back to camelCase
• Updated FiltersScope class to use the config
• Added comprehensive tests for all converter modes
• Resolves the TODO comment in FiltersScope::__invoke()

Backward Compatibility

This change is fully backward compatible. The default behavior (camel) remains unchanged.

Example Usage

// config/query-builder.php
'scope_name_converter' => 'none',

// Now filters respect the exact scope name:
GET /posts?filter[published_at]=2023
// Calls: scopePublished_at() instead of scopePublishedAt()

Resolves TODO in FiltersScope class.