Fix issues with Aux_FindExtrema and Aux_FindWeightedAverageCenter's field preparation time

[hsinhaoHHuang]

Issue

The functions Aux_FindExtrema() and Aux_FindWeightedAverageCenter() can produce inconsistent results when called in the middle of a global simulation step. This occurs because of how they access field data:

• Intrinsic Fields (fluid, potential): These fields are accessed directly using amr->patch[ amr->FluSg[lv] ][lv][PID]->fluid or amr->patch[ amr->PotSg[lv] ][lv][PID]->pot.
• Derived Fields (e.g., TOTAL_DENS): These fields are obtained via Prepare_PatchData().

The inconsistency arises because Prepare_PatchData() previously used Time[lv] as its PrepTime. While this works correctly when these Aux_ functions are called after a complete global step (e.g., in Aux_Record_Center()), it fails when they are called mid-step (e.g., between the fluid and Poisson solvers).

In a mid-step scenario, the intrinsic fluid fields (amr->...->fluid) might have already been updated by the fluid solver, but Time[lv] (and thus the data used by Prepare_PatchData() for derived fields) has not yet been updated to reflect the current state. This leads to a mismatch where intrinsic fields represent the current state within the step, while derived fields still represent the state from the beginning of the step.

Changes

Replace all the Time[lv] with amr->FluSgTime[lv][ amr->FluSg[lv] ] inside both Aux_FindExtrema() and Aux_FindWeightedAverageCenter().
This change ensures consistency because amr->FluSgTime[lv][ amr->FluSg[lv] ] is updated together with amr->patch[ amr->FluSg[lv] ][lv][PID]->fluid in the EvolveLevel.cpp.

Verification

One can temporarily add if ( lv == MAX_LEVEL ) Aux_Record_Center(); in somewhere like this between the fluid and Poisson solvers. The real OPT__RECORD_CENTER should be turned off to avoid confusion.
And then run ELBDM/HaloMerger with HaloMerger_Halo_Num 0 and HaloMerger_Soliton_Num 1 in Input__TestProb. It is compiled with PARTICLE but there is no particle in the simulation.

Record__Center before the changes:

#               Time        Step         MaxDens       MaxDens_x       MaxDens_y       MaxDens_z   ...    MaxTotalDens  MaxTotalDens_x  MaxTotalDens_y  MaxTotalDens_z   ...
3.12211591304518e-04           0   1.2022824e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...   1.2021755e+05   1.2935895e-01   6.4666840e-02   1.2935895e-01   ...
3.12211591304518e-04           0   1.2023956e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...   1.2022824e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2025088e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...   1.2023956e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2026148e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...   1.2025088e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2027082e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...   1.2026148e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2027878e+05   1.2935895e-01   6.4717380e-02   1.2935895e-01   ...   1.2027082e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2028538e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...   1.2027878e+05   1.2935895e-01   6.4717380e-02   1.2935895e-01   ...
3.12211591304518e-04           0   1.2029072e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...   1.2028538e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...
3.12211591304518e-04           0   1.2029492e+05   1.2940949e-01   6.4717380e-02   1.2940949e-01   ...   1.2029072e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...
3.12211591304518e-04           0   1.2029800e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...   1.2029492e+05   1.2940949e-01   6.4717380e-02   1.2940949e-01   ...

-> The MaxDens and MaxTotalDens are different in the same row even though there is no particle. The MaxTotalDens matches the MaxDens in the previous row.

Record__Center after the changes:

#               Time        Step         MaxDens       MaxDens_x       MaxDens_y       MaxDens_z   ...    MaxTotalDens  MaxTotalDens_x  MaxTotalDens_y  MaxTotalDens_z   ...
3.12211591304518e-04           0   1.2022824e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...   1.2022824e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2023956e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...   1.2023956e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2025088e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...   1.2025088e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2026148e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...   1.2026148e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2027082e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...   1.2027082e+05   1.2935895e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2027878e+05   1.2935895e-01   6.4717380e-02   1.2935895e-01   ...   1.2027878e+05   1.2935895e-01   6.4717380e-02   1.2935895e-01   ...
3.12211591304518e-04           0   1.2028538e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...   1.2028538e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...
3.12211591304518e-04           0   1.2029072e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...   1.2029072e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...
3.12211591304518e-04           0   1.2029492e+05   1.2940949e-01   6.4717380e-02   1.2940949e-01   ...   1.2029492e+05   1.2940949e-01   6.4717380e-02   1.2940949e-01   ...
3.12211591304518e-04           0   1.2029800e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...   1.2029800e+05   1.2940949e-01   6.4717380e-02   1.2935895e-01   ...

-> The MaxDens and MaxTotalDens are the same in the same row as expected now.