docs: rebuild system report and test workflow

doc/reports/system/evidence/README.md

@@ -0,0 +1,12 @@
+# Report evidence
+
+Generated logs and Vivado reports used by `system_design_report.tex` live here:
+
+- `soc/`: UART output from SoC simulations
+- `build/`: software build logs for the five selected examples
+- `vivado/`: timing, utilization, CDC, DRC, route and power reports
+- `board/`: official board evaluation output
+
+Run `../tools/run_report_tests.sh refresh` after replacing evidence. Large generated
+artifacts such as `.wdb`, `.jou`, `.str`, implementation checkpoints and bitstreams do
+not belong in this directory.