feat: distributed brain architecture with rqlite and local embeddings (#118)

- Add new brain module with rqlite-based distributed memory and task queue
- Implement BrainClient for memory operations (store, recall, search)
- Implement DistributedWorker for continuous task processing
- Add local embeddings via sentence-transformers (all-MiniLM-L6-v2)
  - No OpenAI dependency, runs 100% local on CPU
  - 384-dim embeddings, 80MB model download
- Deprecate persona system (swarm/personas.py, persona_node.py)
- Deprecate hands system (hands/__init__.py, routes)
- Update marketplace, tools, hands routes for brain integration
- Add sentence-transformers and numpy to dependencies
- All changes backward compatible with deprecation warnings

Co-authored-by: Alexander Payne <apayne@MM.local>

pyproject.toml

@@ -10,6 +10,7 @@ readme = "README.md"
 license = "MIT"
 packages = [
     { include = "config.py", from = "src" },
+    { include = "brain", from = "src" },
     { include = "creative", from = "src" },
     { include = "dashboard", from = "src" },
     { include = "hands", from = "src" },
@@ -43,6 +44,8 @@ websockets = ">=12.0"
 GitPython = ">=3.1.40"
 moviepy = ">=2.0.0"
 requests = ">=2.31.0"
+sentence-transformers = ">=2.0.0"  # Local embeddings for brain
+numpy = ">=1.24.0"
 # Optional extras
 redis = { version = ">=5.0.0", optional = true }
 python-telegram-bot = { version = ">=21.0", optional = true }