Remove MOSS-TTS-Nano backend (not real-time on free CPU tier)

moss: rebuild moss-gen with local KV cache (fork 09308c9, ~1.43x CPU)

moss: persistent moss-gen serve process (kill per-clause gguf reload)

moss: rebuild moss-gen from fork rev dd64994 (MOSS_DIR support)

moss: copy versioned ggml .so (libggml*.so*) — fix moss-gen loader

moss: scope ggml libs to subprocesses (fix llama-cpp libggml clash)

Add MOSS-TTS-Nano 2nd backend (rs.cpp + codec.cpp, ORT-free) with voice clone

Super-squash branch 'main' using huggingface_hub