feat: Add ncurses renderer and example

- **Renderer**: Implemented `clay_renderer_ncurses.c` supporting rectangles, text, borders, and clipping using standard ncurses plotting.
- **Example**: Added `examples/ncurses-example` demonstrating a scrollable "Social Feed" UI with keyboard navigation.
- **Build**: Added `CLAY_INCLUDE_NCURSES_EXAMPLES` option to root `CMakeLists.txt` and integrated the new example.
- **CompConfig**: Updated `.gitignore` to strictly exclude `build/`, `_deps/`, and other standard CMake artifacts.

.gitignore

@@ -1,7 +1,18 @@
-cmake-build-debug/
-cmake-build-release/
 .DS_Store
 .idea/
 node_modules/
 *.dSYM
-.vs/
+.vs/
+
+# CMake dependencies
+_deps/
+
+# CMake build artifacts
+build/
+cmake-build-debug/
+cmake-build-release/
+CPack*
+Makefile
+cmake_install.cmake
+CMakeCache.txt
+CMakeFiles