Pull request overview

This PR fixes a bug introduced in #556 where the old and new state/gradient pressure (gp) arrays were swapped in the velocity projection step. The fix ensures velocity updates are applied to the new state using the old gradient pressure.

Changes:

• Swapped state_old_ma/gp_new_ma to state_new_ma/gp_old_ma in the variable-density branch
• Swapped the same arrays in the constant-density branch

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This seems to have solved the issue on my end and the log file for my runs are now similar to what I had in my previous November version (incl. flamesheet TC). Can't really comment on the appropriateness of the format of the coding but it seems fairly straightforward. Thanks for attending to this so quickly.

Thanks for catching this Bruce - not sure how this got lost in translation in the previous PR; apologies.