feat(memory): add session-based chat history and user metadata retrieval

- Add ChatSessionCache to manage chat history per session
- Add SEARCH_USER_METADATA cypher query for retrieving user entity metadata
- Add "str" mode support to StructResponse for raw text extraction
- Add content_str field to MemorySearchResult for pre-formatted content
- Fix sandbox URL by removing hardcoded port
- Add description field to entity search results
- Remove history from UserInput schema, use session_id instead

api/app/services/draft_run_service.py

@@ -108,6 +108,7 @@ def create_long_term_memory_tool(
         try:
             with get_db_context() as db:
                 memory_service = MemoryService(db, config_id, end_user_id)
+                # TODO: Historical Messages -> Used to refer to coreference resolution
                 search_result = asyncio.run(memory_service.read(question, SearchStrategy.QUICK))
 
             #     memory_content = asyncio.run(