v1.2.0: Performance optimizations and cross-platform improvements

make Tracy an optional library when it is not supported

Initial commit: GPU-accelerated Minecraft clone

VoxelEngine with OpenGL 4.3+ compute shaders for:
- Block rendering with texture atlas
- Flat terrain generation
- TNT explosion physics (supports 10M entities)
- First-person camera movement

Build systems:
- Premake5 for Windows/Visual Studio
- CMake for Linux/WSL

Dependencies now use official upstream repos as submodules:
- GLFW (glfw/glfw)
- Dear ImGui (ocornut/imgui)
- GLM (g-truc/glm)
- spdlog (gabime/spdlog)
- Tracy (wolfpld/tracy)
- raudio (raysan5/raudio)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>