#48 feat: implement versioning logic using git hash or tag

## Issue Description Implement automatic versioning logic for the stable-diffusion.cpp-rest project using git information. ## Requirements 1. **Git-based Version Detection**: - Use git tag if available (prefer annotated tags) - Fall back to git commit hash for development builds - Handle detached HEAD state and tagless repositories 2. **CMake Integration**: - Update CMakeLists.txt to set version variables automatically - Make version available to both C++ backend and web frontend - Support semantic versioning format (vX.Y.Z or X.Y.Z) 3. **Version Display**: - Expose version through API endpoint (e.g., /api/version) - Display version in web UI - Include version in server startup logs 4. **Build Information**: - Include build timestamp - Include build type (Release/Debug) - Include commit hash (even when using tag) ## Implementation Plan - Create version detection script or CMake function - Update main CMakeLists.txt to set version variables - Add version.h header file for C++ backend - Add /api/version endpoint to server.cpp - Update web UI to display version information - Add version to server startup logging ## Expected Outcome - Consistent versioning across all components - Easy identification of build commits - Professional version display in UI and API - Support for both release (tagged) and development builds