GHSA-9fjq-45qv-pcm7: ruint affected by unsoundness of safe `reciprocal_mg10`

The function reciprocal_mg10 is marked as safe but can trigger undefined behavior (out-of-bounds access) because it relies on debug_assert! for safety checks instead of assert!.

When compiled in release mode, the debug_assert! is optimized out, potentially allowing invalid inputs to cause memory corruption.