docs: rebuild system report and test workflow

doc/reports/system/figures/clock_cdc.dot

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+digraph G {
+  graph [rankdir=TB, bgcolor="transparent", pad=0.15, nodesep=0.30, ranksep=0.42,
+         fontname="Noto Sans CJK SC"];
+  node [shape=box, style="rounded,filled", fontname="Noto Sans CJK SC", fontsize=10,
+        color="#44546A", fillcolor="#F7F8FA", margin="0.13,0.08"];
+  edge [fontname="Noto Sans CJK SC", fontsize=9, color="#596777", arrowsize=0.7];
+
+  osc [label="50 MHz 外部时钟"];
+  pll [label="PLL\nlocked", fillcolor="#D9EAF7"];
+  cpu [label="cpu_clk 33.333 MHz\nCPU + AXI CPU 侧", fillcolor="#EAF2F8"];
+  sys [label="sys_clk 50 MHz\nCrossbar / DMA / FFT / matmul", fillcolor="#E8F3E8"];
+  mlk [label="mlkem_clk 76.923 MHz\nML-KEM 计算域", fillcolor="#F8E6EA"];
+  cdc_cpu [label="CPU↔SYS AXI CDC\n异步握手 / FIFO", shape=box, fillcolor="#FFF1D6"];
+  cdc_mlk [label="SYS↔ML-KEM CDC\n命令 / 数据 / 状态同步", shape=box, fillcolor="#FFF1D6"];
+  rst [label="各域复位同步器\n异步置位、同步释放", fillcolor="#F2F2F2"];
+
+  { rank=same; osc; pll; }
+  { rank=same; cpu; cdc_cpu; sys; }
+  { rank=same; cdc_mlk; mlk; }
+  osc -> pll;
+  pll -> cpu;
+  pll -> sys;
+  pll -> mlk;
+  cpu -> cdc_cpu -> sys [dir=both];
+  sys -> cdc_mlk -> mlk [dir=both];
+  pll -> rst [label="locked"];
+  rst -> cpu [style=dashed, label="resetn", constraint=false];
+  rst -> sys [style=dashed, label="resetn", constraint=false];
+  rst -> mlk [style=dashed, label="resetn", constraint=false];
+}