Refactor application to use Qt6, enhance GUI features, and support x64 Linux in batch runs

[SaltyJoss]

This pull request introduces significant improvements to the CMake build system and project structure for better maintainability, platform support, and modularity. Key changes include modernizing and restructuring the CMake configuration, refining preset and workflow usage, and cleaning up the source organization and dependencies.

CMake and Build System Modernization:

• Updated the minimum required CMake version to 3.17 in all relevant CMakeLists.txt files and removed outdated policy handling for MSVC debug information. Output directories are now consistently set using a new OUTPUT_BASE variable. [1] [2]

• Refined and modularized the core library's source structure by splitting source file lists into logical groups (DEP_CORE_SRC, SINGLE_BODY_SYS_SRC, etc.) and updating target_sources accordingly. Improved platform-specific compiler options and visibility settings. [1] [2]

• Enhanced dependency management: removed direct fetching of several dependencies (GLFW, GLM, Assimp, ImGui, ImPlot) from the root CMakeLists.txt, and improved HDF5 linking logic for better compatibility across platforms and package configurations. [1] [2] [3]

CMake Presets and Workflow Improvements:

• Overhauled CMakePresets.json to version 8, introducing new base and GUI presets, platform-specific configurations for Windows and Linux, and new build/test presets for streamlined CI and local development.

• Updated the GitHub Actions workflow (.github/workflows/build.yml) to use the new CMake presets for configure, build, and test steps, ensuring consistency and leveraging the improved preset system.

Project Structure and Conditional Build Logic:

• Refactored DSFE_App/CMakeLists.txt to use an option() for enabling/disabling the GUI module (DSFE_ENABLE_GUI), and conditionally add the DSFE_GUI subdirectory based on this flag.

Header and Source Cleanup:

• Cleaned up includes and removed unnecessary or redundant header inclusions (e.g., <MathLibAPI.h>, pragma warnings) across multiple header files in DSFE_Core, improving clarity and reducing build warnings. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]

Platform and Export Improvements:

• Improved platform detection and symbol export logic for shared libraries, adding GCC/Clang visibility attributes and platform-specific defines. [1] [2] [3]

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Most Important Changes:

CMake and Build System Modernization

• Updated minimum CMake version to 3.17, removed legacy policies, and restructured output directories for consistency. [1] [2]
• Modularized core source file organization and improved platform/compiler options and visibility settings in DSFE_Core. [1] [2]

Dependency and Preset Management

• Removed direct fetching of several dependencies (GLFW, GLM, Assimp, ImGui, ImPlot) and improved HDF5 linking for better platform compatibility. [1] [2] [3]
• Overhauled CMakePresets.json to version 8, introducing new base, GUI, and platform-specific presets for configure/build/test.
• Updated GitHub Actions workflow to leverage new CMake presets for configuration, build, and test steps.

Project Structure and Conditional Logic

• Added DSFE_ENABLE_GUI option and conditional inclusion of the GUI module in the main application CMake file.

Header and Export Improvements

• Cleaned up and unified header includes, removed unnecessary pragmas and headers, and improved cross-platform symbol export logic. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15]