Add memba MVP: C++ core, Python SDK, CLI, examples, experiments

C++ core (libmemba.so):
- include/memba/state.h — C API (state_new/free/save/load/get_size)
- src/state.cpp — MEMB file format: magic, version, SHA-256 model_id,
  CRC-32, opaque llama_state_*_data() blob
- src/cli.cpp — minimal demo binary with greedy sampler
- CMakeLists.txt + build.sh with llama.cpp submodule, CUDA auto-detect

Python SDK (memba):
- core.py — file I/O via llama-cpp-python's exposed C functions,
  unwraps _LlamaContext to access raw context pointer (≥0.3.x)
- session.py — high-level Session with auto-save/load, ChatML wrapper
  for instruct models, raw mode for base models
- cli.py — typer-based: chat (REPL), run (one-shot), list, rm, info

Examples:
- 01_basic_save_load.py, 02_chat_session.py

Experiments (throwaway POCs documenting product-direction findings):
- recall_poc.py — git log → state → cross-process query
- mood_poc.py — batch sentiment trajectory, Mamba vs Transformer
- mood_stream_poc.py, mood_batch_poc.py — variants
- diag_saveload.py — minimal save/load isolation test
- README.md documents the headline finding: save/load is byte-identical,
  but Falcon-Mamba-7B-Instruct does not retain facts across conversation
  turns even in-process — limits viable products to single-prompt analysis
  and persona priming.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

python/memba/__init__.py

@@ -0,0 +1,21 @@
+"""
+memba — persistent memory layer for SSM-based LLMs.
+
+Quickstart
+----------
+    from memba import Session
+
+    s = Session("falcon-mamba-7b-Q4_K_M.gguf", session_id="research")
+    print(s.chat("The Transformer architecture was introduced in 2017."))
+    s.save()
+
+    # Later — same session, picks up where it left off
+    s2 = Session("falcon-mamba-7b-Q4_K_M.gguf", session_id="research")
+    print(s2.chat("Who were the authors?"))
+"""
+
+from .session import Session
+from .core import save_state, load_state, get_state_size, compute_model_id
+
+__all__ = ["Session", "save_state", "load_state", "get_state_size", "compute_model_id"]
+__version__ = "0.1.0"