Update build workflow to statically build Abseil and project dependencies

Modify GitHub Actions workflow to:
- Build Abseil from source statically
- Configure CMake for static linking
- Remove external Abseil library dependency
- Update build flags to support static compilation

.gitignore

@@ -0,0 +1,43 @@
+# CMake build directories
+build/
+CMakeFiles/
+CMakeCache.txt
+cmake_install.cmake
+compile_commands.json
+CTestTestfile.cmake
+Testing/
+_deps/
+
+# Compiled files
+*.o
+*.obj
+*.exe
+*.out
+*.app
+*.dll
+*.so
+*.dylib
+
+# IDE specific files
+.vscode/
+.idea/
+*.swp
+*.swo
+.DS_Store
+
+# Generated files
+Makefile
+*.make
+*.cmake
+!CMakeLists.txt
+
+# Dependencies
+_deps/
+vcpkg_installed/
+
+# Debug symbols
+*.pdb
+*.dSYM/
+
+# Generated documentation
+docs/_build/