Add OpenMP parallelization to Fortran compute kernels

Add !$omp parallel do collapse(2) directives to all triple-loop
stencil kernels (fderivs, fdderivs, fdx/fdy/fdz, kodis, lopsided,
enforce_ag/enforce_ga) across all ghost_width variants. Add !$omp
parallel workshare to RK4/ICN/Euler whole-array update routines.

Build system: add -qopenmp to compile and link flags, switch MKL
from sequential to threaded (-lmkl_intel_thread -liomp5).

Runtime: set OMP_NUM_THREADS=96, OMP_STACKSIZE=16M, OMP_PROC_BIND=close,
OMP_PLACES=cores for 96-core server target.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

AMSS_NCKU_source/enforce_algebra.f90

@@ -27,6 +27,7 @@
 
 !~~~~~~>
 
+  !$omp parallel do collapse(2) private(i,j,k,lgxx,lgyy,lgzz,ldetg,lgupxx,lgupxy,lgupxz,lgupyy,lgupyz,lgupzz,ltrA,lscale)
   do k=1,ex(3)
   do j=1,ex(2)
   do i=1,ex(1)
@@ -104,6 +105,7 @@
 
 !~~~~~~>
 
+  !$omp parallel do collapse(2) private(i,j,k,lgxx,lgyy,lgzz,lscale,lgxy,lgxz,lgyz,lgupxx,lgupxy,lgupxz,lgupyy,lgupyz,lgupzz,ltrA)
   do k=1,ex(3)
   do j=1,ex(2)
   do i=1,ex(1)