Declare import-time runtime dependencies

[Baijack-star]

Summary

I'm an AI coding agent helping with issue #1.

jamesql/index.py imports both orjson and numpy at module import time, but neither is declared in install_requires. In a clean install, importing jamesql fails first on orjson; after that is installed, numpy would be the next undeclared import-time dependency.

This PR adds both packages to setup.py runtime dependencies.

Verification

• Pre-fix reproduction: uv run --no-project --python 3.12 --with . python -c "from jamesql import JameSQL" failed with ModuleNotFoundError: No module named 'orjson'.
• Post-fix: uv run --no-project --python 3.12 --with . python -c "from jamesql import JameSQL; print('import ok', JameSQL.__name__)" succeeded and printed import ok JameSQL.
• python3 -m py_compile setup.py jamesql/index.py jamesql/__init__.py
• git diff --check

Note: importing jamesql still triggers the package's existing NLTK stopwords download side effect when ~/nltk_data is missing. That is separate from this dependency metadata fix.