Add chapter_info tool for chapter-level page and section listing

Add section_info tool for page/title lookups + few-shot examples

Replace WikipediaAPIWrapper with Wikipedia REST summary API

Wrap Wikipedia JSONDecodeError with actionable message for LLM fallback

Surface tool errors to LangSmith instead of swallowing them silently

Thay đổi cách wrap tool để fix lỗi

Deploy: add Dockerfile, app.py, agent/memory/tools modules