Update e2b_charts dependencies: relax numpy constraint and bump versions

- Change numpy from ^1.26.4 to >=1.26.4 to allow numpy 2.x
- Bump matplotlib to ^3.10.3, pydantic to ^2.9.1
- Bump dev deps: pytest to ^8.3.5, python-dotenv to ^1.2.1
- Regenerate poetry.lock

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: mishushakov