Return zero flux below the floor of the AE8/AP8 table, not 1

Add Astropy badge

[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/astral-sh/ruff-pre-commit: v0.14.4 → v0.14.10](astral-sh/ruff-pre-commit@v0.14.4...v0.14.10)

Add code coverage badge

Add physics classifier