embed textures and shaders

[dawc17]

This pull request introduces a new CMake-based system for embedding asset files (textures and shaders) directly into the binary, eliminating the need to load these resources from the filesystem at runtime. It updates the codebase to load all relevant assets from memory, simplifying deployment and improving portability. The changes touch the build system, asset loading logic, and the interface for asset-related functions.

Key changes include:

Build system and asset embedding:

• Added a new CMake macro (embed_resources.cmake) for converting asset files (textures and shaders) into C++ arrays, and generating corresponding header and source files at build time. (cmake/embed_resources.cmake, src/CMakeLists.txt, [1] [2]
• Updated the build configuration to include the generated assets in the build output and to add the generated directory to include paths. (src/CMakeLists.txt, .clangd, [1] [2] [3]
• Removed the previous system for copying shader files at build time, since shaders are now embedded. (src/CMakeLists.txt, src/CMakeLists.txtL47-L76)

Codebase refactoring for embedded assets:

• Replaced all code that loaded textures and shaders from disk with new logic that loads them from the embedded arrays. This affects texture loading in Renderer.cpp, tool model generation in ToolModelGenerator.cpp, and shader loading in ShaderClass.cpp. (src/core/Renderer.cpp, src/rendering/ToolModelGenerator.cpp, src/rendering/opengl/ShaderClass.cpp, [1] [2] [3]
• Updated function signatures and usages to accept asset data and size instead of file paths, and removed now-unnecessary path resolution logic. (src/core/MainGlobals.cpp, src/core/MainGlobals.h, [1] [2] [3]

Interface and header changes:

• Updated function signatures for texture and tool model loading to use embedded data buffers, and removed unused or obsolete interfaces. (src/core/MainGlobals.h, src/rendering/ToolModelGenerator.h, [1] [2]

General code clean-up:

• Removed error messages and fallback logic related to missing files on disk, since assets are now always available in the binary. (src/core/Renderer.cpp, src/core/Renderer.cppL89)

Source file includes:

• Added includes for the generated embedded_assets.h where needed. (src/core/MainGlobals.cpp, src/core/Renderer.cpp, src/rendering/ToolModelGenerator.cpp, src/rendering/opengl/ShaderClass.cpp, [1] [2] [3] [4]