[Release v1.0] Add missing query builder methods, api resources, and other improvements

[ianhalpern]

Description

Major update to the Payload PHP SDK bringing it up to parity with the Node.js SDK. Adds missing query builder methods, new API resource classes, improved subclass discovery, and reorganized tests.

Changes include:

• Add order_by, limit, and offset methods to ARMRequest and ARMObject for query building
• Add default_params support on ARMObject subclasses, applied automatically to requests (user params take precedence)
• Add InvoiceAttachment, WebhookLog, and Ledger API resource classes
• Replace get_declared_classes() subclass scan in Utils::data2object with a lazy-loading registry on ARMObject that auto-discovers all classes via glob(__DIR__) + require_once
• Fix group_by in ARMRequest incorrectly writing to fields param instead of group_by
• Fix endpoint generation to handle object names already ending in 's'
• Refactor ARMObject to use _build_request helper for consistent request construction
• Declare ARMRequest properties explicitly (PHP 8.2+ compatibility)
• Change include() to require_once() for Exceptions loading
• Reorganize tests into Tests/Unit and Tests/Int directories
• Add QueryParamsTest unit tests covering order_by, limit, offset, chaining, and default_params
• Split CI workflow to run unit tests separately from integration tests
• Apply phpcbf code formatting across all files

Type of change

• New feature (non-breaking change which adds functionality)
• Enhancement (non-breaking change which enhances functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Potential breaking change

Utils::data2object now uses a lazy-loading registry that auto-discovers all class files in the Payload/ directory via glob() + require_once. Previously, if a class file wasn't explicitly loaded, nested objects of that type would be left as plain associative arrays. Now all classes are always loaded, so nested objects will be deserialized into class instances where they previously may have remained arrays. Any code that accesses nested objects using array syntax (e.g. $val['key']) instead of property access (e.g. $val->key) may break.

[russellw-dev]

If we're converting the $obj parameter to an array/list on line 199, wouldn't this if condition never be called?

[ianhalpern]

We're only converting it to an array/list if it's a regular array instead of a associative array

[russellw-dev]

Could be wrong here but in looking at how static properties/inheritance work in PHP, it looks like if we set this on a subclass it will then set it for every other subclass, which it looks like the test here is doing - is that something we want to happen?

[ianhalpern]

Oh yea, looks like that's right. Awesome find, will fix.

[russellw-dev]

In Payload/API.php and composer.json should we bump the version to 1.0.0 per the branch name?