MUSCL THINC right-state reconstruction uses already-overwritten left-state values #1200
Description
Bug
In `src/simulation/m_muscl.fpp`, the THINC interface reconstruction computes the left-state first, overwriting the density ratio values. The subsequent right-state computation reads these already-overwritten values instead of the original ones.
File: `src/simulation/m_muscl.fpp`, lines 285-301
Impact: Right-state THINC reconstruction uses contaminated density ratios from the left-state computation. Currently masked by algebraic coincidence in simple cases, but produces wrong results when left and right densities differ significantly.
Severity: High — silent corruption of MUSCL-THINC interface reconstruction.