OpenSystemsDevelopment / qpdf

…tionary, modernize constructors, and clean up null handling logic.

…up method implementations, and simplify member handling.

…ed_ptr and forward declaration.

Add `nullify` method to `BaseHandle` for setting objects to a mutable…

Add private-API Null class

…ent and simplified temporary null management. Clean up unused test coverage markers.

…ent and simplified temporary null management. Clean up unused test coverage markers.

Prevent infinite recursion in /AcroForm traversal by checking for sel…

Refactor integer handling and type conversions

Simplify integer value retrieval by introducing a templated `value` method in the `Integer` class. Replace redundant exception handling logic across multiple functions with this unified approach. Streamline type conversions and improve readability.

Refactor Stream factories

…arameters with their existing empty values.

…e parameters with their existing values.

Refactor QPDFFormFieldObjectHelper and QPDFEFStreamObjectHelper

…ng handling with `qpdf::String`, and clean up `Members` class implementation.

…ant logic, and streamline type conversions.

…::types` helpers, simplify pipeline usage, and clean up includes.

Refactor QPDFParser

… clean up unused file.

…and simplify pipeline logic.

…nt checks, and streamline string handling.

…` file and eliminate unneccessary creation of `Members` object.

…sting return values for uninitialized objects, and cleaning up error handling logic.

…ndles on invalid input..

…eplacing redundant logic with centralized functions, and streamlining bad token handling for improved readability and maintainability.

…raints, replacing hardcoded values for nesting, container size, and error limits.

Minor refactorings

… for improved code readability and maintainability.

… simplify logic. Update related test outputs and release notes.

Add new private-API class String

…` and replace with `String::utf16`.

Added `qpdf::String` class to encapsulate string operations. Updated `QPDFObjectHandle` string methods to utilize `qpdf::String`, streamlined empty string handling, and removed redundant test coverage entries.

…oved shared pointer handling, remove deprecated object methods, and update all references.