made local rag needs optional (prevents having to have torch / sentence-transformers if you never use local embedding)

tests/test_rag_engine.py

@@ -2,6 +2,7 @@ import pytest
 import os
 from unittest.mock import MagicMock, patch
 from src import models
+from src import rag_engine
 from src.rag_engine import RAGEngine, BaseEmbeddingProvider, LocalEmbeddingProvider, GeminiEmbeddingProvider
 
 class MockEmbeddingProvider(BaseEmbeddingProvider):
@@ -11,13 +12,19 @@ class MockEmbeddingProvider(BaseEmbeddingProvider):
 @pytest.fixture
 def mock_rag_config():
  vs_config = models.VectorStoreConfig(provider='mock', collection_name='test')
- return models.RAGConfig(enabled=True, vector_store=vs_config, embedding_provider='local')
+ return models.RAGConfig(enabled=True, vector_store=vs_config, embedding_provider='gemini')
 
 def test_rag_engine_init_mock(mock_rag_config):
  engine = RAGEngine(mock_rag_config)
  assert engine.config.enabled is True
  assert engine.collection == "mock"
 
+def test_local_embedding_provider_missing_dependency_has_install_hint():
+ with patch.object(rag_engine, "_SENTENCE_TRANSFORMERS", None):
+  with patch.dict("sys.modules", {"sentence_transformers": None}):
+   with pytest.raises(ImportError, match=r"manual_slop\[local-rag\]"):
+    LocalEmbeddingProvider()
+
 @patch('src.rag_engine.LocalEmbeddingProvider.embed')
 @patch('src.rag_engine._get_chromadb')
 def test_rag_engine_chroma(mock_get_chroma, mock_embed):