OpenSystemsDevelopment / qpdf

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.

…DFObjectHandle` storage, remove unused trace calls, and streamline invalid handle checks.

…sages, and clean up `QPDF.hh`.

… and `findEndstream` to `Objects`, remove `QPDF::PatternFinder` class, and update related logic for improved encapsulation.

…, replace direct calls with `QIntC` equivalents, and clean up `QPDF.hh`.

…t` consistency to handle invalid entries, and improve loop detection logic.

…` parameter, update conditional checks, and streamline logic for field and annotation handling.

Tighten validation of the PDF spec requirements that form fields form a tree and that widget annotations have a single parent by utilizing `field_to` and `annotation_to_field` in the loop detection check.

…d calls, and streamline related logic for improved encapsulation and maintainability.

…with encapsulated `Config`, replace `qcf` with `d_cfg` for improved consistency, and adjust related logic for maintainability.

…shared` for progress reporters to improve clarity and efficiency.

…on` checks, consolidate parameter updates, and remove redundant code for improved clarity.

… parameter handling, and adjust related method calls for improved maintainability and readability.

…or `extension_level` in `setMinimumPDFVersion`, and update calls for improved encapsulation.

…date logic, and improve encapsulation.

…to `impl::Writer`, streamline initialization, and enhance encapsulation.

…nfig` struct, update member access to use `cfg`, and streamline related logic across `QPDFWriter`.

…c::Common`, and adjust related `QPDFWriter` logic for improved encapsulation.

…:Doc`, rename related methods, and streamline usage across QPDFWriter and linearization modules.

… `Objects`, and `Pages` to use it, and streamline initialization logic.

… declarations across the codebase for improved encapsulation.

…c across `QPDFWriter` for consistency and improved readability.

…isting code used 'last_object_description' and reported the error against a random unrelated object.

…sed_after_compressed` in `QPDF::Doc::Objects`, update usage in `QPDF_linearization`, and streamline related logic.

…ate usage across `QPDF_linearization`, and streamline related logic.

…`Lin`, encapsulate optimization data within `Lin`, update usage across the codebase, and streamline related logic in `QPDF_linearization`.

…ed`, `check`, and `show_data` methods, update usage across the codebase, and streamline related logic.

… `attempt_recovery` to `password_is_hex_key` and `suppress_recovery` to align with the CLI, update usage across the codebase, and streamline related logic.

…` methods, update usage across codebase, and streamline related logic.

…fields, replace direct member access across the codebase, and streamline related logic.

…te usage throughout the codebase, and streamline configurations.

…r` for cleaner and more concise overflow checks.

…for improved structure and better code locality.

…ine logic, update calls across codebase, and streamline method implementation.

… `QPDFPageDocumentHelper`, consolidate redundant logic, and streamline method calls.

…e includes, and streamline page-related logic.

…gin`/`end` methods, update calls across codebase, and streamline page handling logic.