v7.4: Package MAGI with pyproject and CLI entry points

[LucaXTech]

Packages MAGI as an installable Python project and adds production-style CLI entry points.

Changes:

• add pyproject.toml with runtime/dev dependency metadata
• expose magi-web, bioaudit-web, and magi-benchmark-validate
• preserve existing python -m ... execution paths
• include MAGI static UI assets and benchmark JSON/JSONL data in package distributions
• update CI to install the package with pip install -e ".[dev]" on Python 3.11 and 3.12
• smoke-test the installed CLI entry points in CI
• add packaging regression tests
• update README Quick Start
• ignore generated packaging artifacts

Validation performed locally:

• 52 pytest tests passed
• locked benchmark validation passed
• editable install succeeded
• wheel build succeeded
• wheel package data verified
• CLI entry points verified

Closes #3