Provide a language-agnostic C99 bridge using standard C types (const char*,
void*, int64_t, etc.) so MMKV Core can be consumed from C-only environments
- Core/cbridge/MMKVBridge.h: pure C header with mmkv_ prefixed API
- Core/cbridge/MMKVBridge.cpp: implementation wrapping MMKV C++ API
- POSIX/demo/demo_c.c: pure C demo exercising all API surface
- CMakeLists.txt updates for core library and demo_c target