Add OpenMP parallelization to BSSN RHS hot-path stencil routines

Enable OpenMP threading for the dominant computational kernels:
- makefile.inc: add -qopenmp to f90appflags
- diff_new.f90: split fderivs/fdderivs into OpenMP interior + serial boundary
- kodiss.f90: split kodis into OpenMP interior + serial boundary
- lopsidediff.f90: add OMP PARALLEL DO COLLAPSE(2) to lopsided
- fmisc.f90: parallelize symmetry_bd bulk array copy
- bssn_rhs.f90: add OMP WORKSHARE to array-syntax operations

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

AMSS_NCKU_source/fmisc.f90

@@ -881,9 +881,18 @@ subroutine symmetry_bd(ord,extc,func,funcc,SoA)
   real*8, dimension(-ord+1:extc(1),-ord+1:extc(2),-ord+1:extc(3)),intent(out):: funcc
   real*8, dimension(1:3), intent(in) :: SoA
 
-  integer::i
+  integer::i,j,k
+
+  !$OMP PARALLEL DO COLLAPSE(2) SCHEDULE(static) PRIVATE(i,j,k)
+  do k=1,extc(3)
+  do j=1,extc(2)
+  do i=1,extc(1)
+     funcc(i,j,k) = func(i,j,k)
+  enddo
+  enddo
+  enddo
+  !$OMP END PARALLEL DO
 
-  funcc(1:extc(1),1:extc(2),1:extc(3)) = func
    do i=0,ord-1
       funcc(-i,1:extc(2),1:extc(3)) = funcc(i+1,1:extc(2),1:extc(3))*SoA(1)
    enddo