mlkem_top now instantiates comp_decomp_sync (E5), so the shared
xsim_run.tcl must compile it (+ its pipeline_reg dep) before mlkem_top.
This unbreaks 'run_tb.sh top' which failed elaboration with
'Module comp_decomp_sync not found'. run_enc.sh simplified to reuse the
tcl's now-complete compile list (drops its duplicate leaf block).