Fix bc_x%ve3 never MPI-broadcast (duplicate ve2 instead)

The bc_x velocity-end broadcast list has bc_x%ve2 duplicated where
bc_x%ve3 should be. bc_y and bc_z rows are correct. Non-root ranks
get uninitialized bc_x%ve3 in multi-rank 3D runs with x-boundary
velocity BCs.

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

Author: sbryngelson

src/simulation/m_mpi_proxy.fpp

@@ -145,7 +145,7 @@ contains
 
         #:for VAR in [ 'dt','weno_eps','teno_CT','pref','rhoref','R0ref','Web','Ca', 'sigma', &
             & 'Re_inv', 'poly_sigma', 'palpha_eps', 'ptgalpha_eps', 'pi_fac',    &
-            & 'bc_x%vb1','bc_x%vb2','bc_x%vb3','bc_x%ve1','bc_x%ve2','bc_x%ve2', &
+            & 'bc_x%vb1','bc_x%vb2','bc_x%vb3','bc_x%ve1','bc_x%ve2','bc_x%ve3', &
             & 'bc_y%vb1','bc_y%vb2','bc_y%vb3','bc_y%ve1','bc_y%ve2','bc_y%ve3', &
             & 'bc_z%vb1','bc_z%vb2','bc_z%vb3','bc_z%ve1','bc_z%ve2','bc_z%ve3', &
             & 'bc_x%pres_in','bc_x%pres_out','bc_y%pres_in','bc_y%pres_out', 'bc_z%pres_in','bc_z%pres_out', &