test: add board FFT validation and VCD capture

doc/reports/system/tools/run_report_tests.sh

@@ -50,11 +50,16 @@ Commands:
   prepare       Create evidence directories and Vivado project if absent
   lint          Run the project-aware Verilator lint check
   build         Build asm, fft, fft_dma, mlkem_test and mlkem_hello
-  soc           Build all five; simulate all except board-only asm
+  soc           Build all five; simulate mlkem_test and mlkem_hello
+  soc-fft       Explicitly run the long fft and fft_dma simulations
   implement     Run Vivado implementation and collect PPA/CDC/DRC reports
   refresh       Parse collected evidence, regenerate figures and build the PDF
   quick         Run lint and refresh only; does not run Vivado implementation
 
+Set SAVE_VCD=1 for SoC simulations to write evidence/soc/<example>.vcd.
+Set VCD_SCOPE to a Vivado hierarchy glob to limit waveform size.
+Set SIM_RUN_TIME only for bounded waveform diagnostics; regressions use 'all'.
+
 Board-only tests (matmul official 5000-group timing and reset behavior) are
 listed in REPORT_RERUN_CHECKLIST.md and are intentionally not automated here.
 EOF
@@ -95,21 +100,31 @@ build() {
 
 run_soc_case() {
   local example="$1"
+  local vcd_path="$EVIDENCE_DIR/soc/$example.vcd"
   require_vivado
   build_example "$example"
-  (cd "$ROOT/fpga" && "$VIVADO_BIN" -mode batch \
+  if [[ "${SAVE_VCD:-0}" != "0" ]]; then
+    echo "VCD output: $vcd_path (scope: ${VCD_SCOPE:-top-level control signals})"
+  fi
+  (cd "$ROOT/fpga" && SOC_VCD_PATH="$vcd_path" "$VIVADO_BIN" -mode batch \
     -source "$SCRIPT_DIR/run_soc_sim.tcl") 2>&1 | tee "$EVIDENCE_DIR/soc/$example.log"
 }
 
 soc() {
   prepare
   build_example asm
-  run_soc_case fft
-  run_soc_case fft_dma
+  build_example fft
+  build_example fft_dma
   run_soc_case mlkem_test
   run_soc_case mlkem_hello
 }
 
+soc_fft() {
+  prepare
+  run_soc_case fft
+  run_soc_case fft_dma
+}
+
 implement() {
   prepare
   require_vivado
@@ -130,6 +145,7 @@ case "${1:-}" in
   lint) lint ;;
   build) build ;;
   soc) soc ;;
+  soc-fft) soc_fft ;;
   implement) implement ;;
   refresh) refresh ;;
   quick) lint; refresh ;;