docs(design): 解压 Maestro Design System 到 design/（重构参照材料）

phosphor console v1.1 设计系统（从现网 web/style.css 演化）：tokens(colors/effects/
typography/fonts) + components(core/forms/surfaces .jsx) + ui_kits(console + console_mobile)
+ assets/icons(15 双色 SVG) + guidelines + CLAUDE/SKILL/readme。供 B1–B6 重构任务对照实现。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

design/components/forms/ComplexitySeg.jsx

@@ -0,0 +1,32 @@
+const css = `
+.m-seg{display:inline-flex;border:1px solid var(--line);font-family:var(--mono);border-radius:var(--radius-sm,4px);overflow:hidden}
+.m-seg button{font-family:var(--mono);padding:7px 13px;cursor:pointer;font-size:11px;font-weight:700;letter-spacing:.12em;color:var(--faint);background:transparent;border:none;border-radius:0}
+.m-seg button + button{border-left:1px solid var(--line)}
+.m-seg button.on-hard{background:var(--red-dim);color:var(--red)}
+.m-seg button.on-medium{background:var(--amber-dim);color:var(--amber)}
+.m-seg button.on-easy{background:var(--green-dim);color:var(--green)}
+.m-seg button.on-auto{background:var(--cyan-dim);color:var(--cyan)}
+`;
+function ensureCss() {
+  if (typeof document === 'undefined' || document.getElementById('m-seg-css')) return;
+  const s = document.createElement('style'); s.id = 'm-seg-css'; s.textContent = css;
+  document.head.appendChild(s);
+}
+const BASE_OPTS = [['hard', 'HARD'], ['medium', 'MEDIUM'], ['easy', 'EASY']];
+
+export function ComplexitySeg({ value, defaultValue = 'medium', onChange, includeAuto, autoLabel = 'AUTO', labels }) {
+  ensureCss();
+  const [inner, setInner] = React.useState(defaultValue);
+  const cur = value !== undefined ? value : inner;
+  const opts = includeAuto ? [...BASE_OPTS, ['auto', autoLabel]] : BASE_OPTS;
+  return (
+    <span className="m-seg">
+      {opts.map(([v, lab]) => (
+        <button key={v} type="button" className={cur === v ? 'on-' + v : ''}
+          onClick={() => { setInner(v); if (onChange) onChange(v); }}>
+          {(labels && labels[v]) || lab}
+        </button>
+      ))}
+    </span>
+  );
+}