Add comprehensive tests for vector/semantic search functionality

- Implement full coverage tests for Embedder model loading and embedding generation
- Add CRUD operations and caching tests for VectorStore
- Include cosine similarity computation tests
- Validate semantic search accuracy and relevance through various queries
- Establish performance benchmarks for embedding and search operations
- Ensure edge cases and error handling are covered
- Test thread safety and concurrent access scenarios
- Verify availability of semantic search dependencies

.claude/rules/active_memory_config.json

@@ -0,0 +1,4 @@
+{
+  "interval": "manual",
+  "tool": "gemini"
+}